We Keep Coding

Value Error: shape mismatch: objects cannot be broadcast to a single shape

I'm making a realtime audio visualizer in python with pyaudio and using matplotlib to plot a graph. When the code reaches the line shown in the code it gives a Value Error: shape mismatch: objects cannot be broadcast to a single shape. and also says there was an Exception in Tkinter callback. I've tried looking everywhere but I couldn't find anything about this. Also when I remove the line that is causing that error, the code works just fine. Any idea how this can be fixed?
Code:
p = pyaudio.PyAudio()
stream = p.open(format=pyaudio.paInt16,
channels=channelcount,
rate=int(device_info["defaultSampleRate"]),
input=True,
frames_per_buffer=defaultframes,
input_device_index=device_info["index"],
as_loopback=True)
fig, (ax, ax2) = plt.subplots(2, figsize=(15, 8))
x = np.arange(0, 2 * CHUNK, 2)
x_fft = np.linspace(0, device_info["defaultSampleRate"], CHUNK)
line, = ax.plot(x, np.random.rand(CHUNK), '-', lw=2)
line_fft, = ax2.semilogx(x_fft, np.random.rand(CHUNK), '-', lw=2)
offset = 2000
ax.set_ylim(0, offset)
ax.set_xlim(0, 2 * CHUNK)
plt.setp(ax, xticks=[0, CHUNK, 2 * CHUNK], yticks=[0, 128, 255])
ax2.set_xlim(20, device_info["defaultSampleRate"] / 2)
ax2.set_ylim(0, 20)
fig.show()
while True:
data = stream.read(CHUNK)
data_int = struct.unpack(str(2 * CHUNK) + 'h', data)
line.set_ydata(np.array(data_int)) <------------------------------- ERROR HAPPENS HERE
y_fft = fft(data_int)
line_fft.set_ydata(np.abs(y_fft[0:CHUNK]) * 2 / (256 * CHUNK))
fig.canvas.draw()
fig.canvas.flush_events()
Error:
Traceback (most recent call last):
File "E:\Python\lib\tkinter\__init__.py", line 1705, in __call__
return self.func(*args)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\_backend_tk.py", line 259, in resize
self.draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_tkagg.py", line 9, in draw
super(FigureCanvasTkAgg, self).draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_agg.py", line 393, in draw
self.figure.draw(self.renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\figure.py", line 1736, in draw
renderer, self, artists, self.suppressComposite)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\axes\_base.py", line 2630, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 759, in draw
self.recache()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 679, in recache
self._xy = np.column_stack(np.broadcast_arrays(x, y)).astype(float)
File "<__array_function__ internals>", line 6, in broadcast_arrays
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 264, in broadcast_arrays
shape = _broadcast_shape(*args)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 191, in _broadcast_shape
b = np.broadcast(*args[:32])
ValueError: shape mismatch: objects cannot be broadcast to a single shape
Exception in Tkinter callback
Traceback (most recent call last):
File "E:\Python\lib\tkinter\__init__.py", line 1705, in __call__
return self.func(*args)
File "E:\Python\lib\tkinter\__init__.py", line 749, in callit
func(*args)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\_backend_tk.py", line 270, in idle_draw
self.draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_tkagg.py", line 9, in draw
super(FigureCanvasTkAgg, self).draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_agg.py", line 393, in draw
self.figure.draw(self.renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\figure.py", line 1736, in draw
renderer, self, artists, self.suppressComposite)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\axes\_base.py", line 2630, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 759, in draw
self.recache()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 679, in recache
self._xy = np.column_stack(np.broadcast_arrays(x, y)).astype(float)
File "<__array_function__ internals>", line 6, in broadcast_arrays
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 264, in broadcast_arrays
shape = _broadcast_shape(*args)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 191, in _broadcast_shape
b = np.broadcast(*args[:32])
ValueError: shape mismatch: objects cannot be broadcast to a single shape
Traceback (most recent call last):
File "E:/PycharmProjects/LedProject/test3.py", line 112, in <module>
fig.canvas.draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_tkagg.py", line 9, in draw
super(FigureCanvasTkAgg, self).draw()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\backends\backend_agg.py", line 393, in draw
self.figure.draw(self.renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\figure.py", line 1736, in draw
renderer, self, artists, self.suppressComposite)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\axes\_base.py", line 2630, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\image.py", line 137, in _draw_list_compositing_images
a.draw(renderer)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\artist.py", line 38, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 759, in draw
self.recache()
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\matplotlib\lines.py", line 679, in recache
self._xy = np.column_stack(np.broadcast_arrays(x, y)).astype(float)
File "<__array_function__ internals>", line 6, in broadcast_arrays
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 264, in broadcast_arrays
shape = _broadcast_shape(*args)
File "E:\PycharmProjects\LedProject\venv\lib\site-packages\numpy\lib\stride_tricks.py", line 191, in _broadcast_shape
b = np.broadcast(*args[:32])
ValueError: shape mismatch: objects cannot be broadcast to a single shape```

Creating a histogram and understanding both maplotlib axes and subplot

I've just had some trouble piecing together matplotlib documentation particularly for my data set. I think I have a small enough block of code that shows all of my lack of understanding despite reading documentation. The documentation i've beeen trying to use for reference was initially this for creating a line graph https://matplotlib.org/gallery/text_labels_and_annotations/date.html
I've been trying to plot a numpy array, post_records containing two columns. I'm working with social media data, so the first column is for post_ids and the second is for datetime_obj_col that I managed to read from csv file using some scripting.
I managed to create a line graph with this data in matplotlib, but I don't quite know how to make a histogram.
Right now, nothing shows up when I run my program
fig, ax = plt.subplots()
hist, bins, patch_lst = ax.hist(post_records[:,1], bins=range(31)) # thought that bins could be a sequence, wanted to create 31 bins for 31 total days in a month
ax.plot(hist, bins)
ax.set_xlabel('Days')
ax.set_ylabel('frequency')
ax.set_title(r'Histogram of Time')
plt.show() # shows nothing
What do I need to pass to ax.plot? I'm unclear about how to pass in my x dataset
why isn't the window showing?
Edit with how to replicate this:
def create_dataframe_of_datetime_objects_and_visualize():
datetime_lst = [1521071920000000000, 1521071901000000000, 1521071844000000000, 1521071741000000000, 1521071534000000000] # to get this variable I loaded my original dataframe with 1980000, sliced the first 5 entries, then printed out the 'datetime_obj_col'. I can't exactly remember what this format is called, I think it's unix time.
id_lst = [974013, 974072, 327212, 123890, 438201]
for each in range(len(datetime_lst)):
datetime_lst[each] = pd.to_datetime(datetime_lst[each], errors='coerce')
datetime_lst[each] = datetime_lst[each].strftime("%d-%b-%y %H:%M:%S")
datetime_lst[each] = pd.to_datetime(datetime_lst[each], errors='coerce', dayfirst=True, format="%d-%b-%y %H:%M:%S")
datetime_lst = pd.Series(datetime_lst)
df = pd.DataFrame({'tweet_id':id_lst, 'datetime_obj_col': datetime_lst})
gb_var = df.groupby(df["datetime_obj_col"].dt.month)
gb_var_count = gb_var.count()
gb_var.plot(kind="bar")
plt.show()
note that I am not using histogram anymore. But there should be two errors that come up, the following:
Traceback (most recent call last):
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 918, in apply
result = self._python_apply_general(f)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 936, in _python_apply_general
self.axis)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 2273, in apply
res = f(group)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 541, in f
return self.plot(*args, **kwargs)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 2941, in call
sort_columns=sort_columns, **kwds)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 1977, in plot_frame
**kwds)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 1804, in _plot
plot_obj.generate()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 266, in generate
self._post_plot_logic_common(ax, self.data)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 405, in _post_plot_logic_common
self._apply_axis_properties(ax.yaxis, fontsize=self.fontsize)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 478, in _apply_axis_properties
labels = axis.get_majorticklabels() + axis.get_minorticklabels()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1245, in get_majorticklabels
ticks = self.get_major_ticks()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1396, in get_major_ticks
numticks = len(self.get_major_locator()())
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1249, in call
self.refresh()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1269, in refresh
dmin, dmax = self.viewlim_to_dt()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1026, in viewlim_to_dt
.format(vmin))
ValueError: view limit minimum 0.0 is less than 1 and is an invalid Matplotlib d
ate value. This often happens if you pass a non-datetime value to an axis that h
as datetime units
Edit:
This is starting to seem like a bug related specifically to trying to use hist() to plot a column of datetime objects.
I took data from post_records which is a loaded numpy array that stores a 2d data set of 198000+ post ids and datetime objects.
This is the code for a function called create datetime objects. It opens a csv file "tweet_time_info_preprocessed.csv," which only has three columns: 'tweet_id" "tweet_created_at_date," and "tweet_created_at_hour." The following is code to combine the tweet_created_at_date and tweet_created_at_hour columns into formatted datetime objects using the pandas library to_datetime() method.
Csv file sample
def create_datetime_objects():
with open("post_time_info_preprocessed.csv", 'r', encoding='utf8') as time_csv:
mycsv = csv.reader(time_csv)
progress = 0
for row in mycsv:
progress +=1
if progress == 1: #header row
continue
if progress % 10000 == 0:
print(progress)
each_post_datetime_lst = []
each_post_datetime_lst.append(row[0])
time_str = str(row[1]) + " " + str(row[2])
a_date_object = pd.to_datetime(time_str, dayfirst=True, format="%d-%b-%y %H:%M:%S")
each_post_datetime_lst.append(a_date_object)
post_and_datetime_lst.append(each_tweet_datetime_lst)
numpy_arr_of_tweets_and_datetimes = np.array(tweets_and_datetime_objs)
np.save(np_save_path, numpy_arr_of_tweets_and_datetimes)
then I have visualize_objects_histogram()
def visualize_objects_histogram():
print("Visualizing timeplot as histogram")
post_records= np.load("tweets_and_datetime_objects.npy")
df = pd.DataFrame(data=post_records, columns=['post_id', 'datetime_obj_col'])
df_sliced = df[0:5]
print(df_sliced)
fig, ax = plt.subplots()
hist, bins, patch_lst = ax.hist(df_sliced['datetime_obj_col'], bins=range(5))
ax.plot(hist, bins)
ax.set_xlabel('Days')
ax.set_ylabel('frequency')
ax.set_title('Histogram of Time')
plt.show()
So I sliced off 5 rows of the data frame and stored them into df_slice. I run this code, a blank white window appears. Printing df_slice gives
tweet_id datetime_obj_col
0 974072352958042112 2018-03-14 23:58:40
1 974072272578166784 2018-03-14 23:58:21
2 974072032177598464 2018-03-14 23:57:24
3 974071601313533953 2018-03-14 23:55:41
4 974070732777914368 2018-03-14 23:52:14
And there's also an error message that comes with the blank white window. It's very long.
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\biney\AppData\Local\Programs\Python\Python36-32\lib\tkinter__i
nit__.py", line 1699, in call
return self.func(*args)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
backends_backend_tk.py", line 227, in resize
self.draw()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
backends\backend_tkagg.py", line 12, in draw
super(FigureCanvasTkAgg, self).draw()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
backends\backend_agg.py", line 433, in draw
self.figure.draw(self.renderer)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
figure.py", line 1475, in draw
renderer, self, artists, self.suppressComposite)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
image.py", line 141, in _draw_list_compositing_images
a.draw(renderer)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axes_base.py", line 2607, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
image.py", line 141, in _draw_list_compositing_images
a.draw(renderer)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1190, in draw
ticks_to_draw = self._update_ticks(renderer)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1028, in _update_ticks
tick_tups = list(self.iter_ticks()) # iter_ticks calls the locator
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 971, in iter_ticks
majorLocs = self.major.locator()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1249, in call
self.refresh()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1269, in refresh
dmin, dmax = self.viewlim_to_dt()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1026, in viewlim_to_dt
.format(vmin))
ValueError: view limit minimum -0.19500000000000003 is less than 1 and is an inv
alid Matplotlib date value. This often happens if you pass a non-datetime value
to an axis that has datetime units
This error message repeats 5 times with slightly different values for the "view limit." Possibly 5 error messages ffor my 5 records. I think the error messages are most closely related to the following online version of dates.py... Could be wrong : https://fossies.org/linux/matplotlib/lib/matplotlib/dates.py (around line 1022, I'm going to check the actual file on my computer soon).
I'm going to try stuff from this post to see if it will help: Can Pandas plot a histogram of dates?
Edit 2:
The previous stackoverflow introduced me to two helpful methods, but they didn't work. I changed my visualize... function to the following
def visualize_datetime_objects_with_pandas():
tweets_and_datetime_objects = np.load("tweets_and_datetime_objects.npy") # contains python datetime objects
print("with pandas")
print(tweets_and_datetime_objects.shape)
df = pd.DataFrame(data=tweets_and_datetime_objects, columns=['tweet_id', 'datetimeobj'])
pandas_freq_dict = df['datetimeobj'].value_counts().to_dict()
#print(pandas_freq_dict)
print(len(list(pandas_freq_dict.keys())))
print(list(pandas_freq_dict.keys())[0])
print(list(pandas_freq_dict.values())[1])
plt.plot(pandas_freq_dict.keys(), pandas_freq_dict.values())
#df = df.set_index('datetimeobj')
# changing the index of this dataframe to a time index
#df['datetimeobj'].plot(kind='line', style=['--'])
plt.show()
It gives the following output/error message.
date-time temporal data visualization script
Visualizing timeplot as histogram
tweet_id datetime_obj_col
datetime_obj_col
14 5 5
tweet_id datetime_obj_col
datetime_obj_col
14 5 5
Traceback (most recent call last):
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 918, in apply
result = self._python_apply_general(f)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 936, in _python_apply_general
self.axis)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 2273, in apply
res = f(group)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\core
\groupby\groupby.py", line 541, in f
return self.plot(*args, **kwargs)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 2941, in call
sort_columns=sort_columns, **kwds)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 1977, in plot_frame
**kwds)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 1804, in _plot
plot_obj.generate()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 266, in generate
self._post_plot_logic_common(ax, self.data)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 405, in _post_plot_logic_common
self._apply_axis_properties(ax.yaxis, fontsize=self.fontsize)
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\pandas\plot
ting_core.py", line 478, in _apply_axis_properties
labels = axis.get_majorticklabels() + axis.get_minorticklabels()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1245, in get_majorticklabels
ticks = self.get_major_ticks()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
axis.py", line 1396, in get_major_ticks
numticks = len(self.get_major_locator()())
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1249, in call
self.refresh()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1269, in refresh
dmin, dmax = self.viewlim_to_dt()
File "C:\Users\biney\AppData\Roaming\Python\Python36\site-packages\matplotlib\
dates.py", line 1026, in viewlim_to_dt
.format(vmin))
ValueError: view limit minimum 0.0 is less than 1 and is an invalid Matplotlib d
ate value. This often happens if you pass a non-datetime value to an axis that h
as datetime units

Exception in Tkinter callback when using Matplotlib due to permission error

I recently set up Ipython on my laptop and wrote this snippet to test the matplotlib installation only to be greeted by this error, the end of the traceback says PermissionError: [Errno 13] Permission denied: 'C:\Users\KARTHIK KC\.matplotlib\fontList.py3k.cache'. I have been unable to resolve this error. Any suggestions?
import matplotlib.pyplot as plt
x = range(-10, 10,1)
y = []
for xi in x:
yi = xi**2
y.append(yi)
plt.plot(x,y)
plt.show()
And this is the error -
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python34\lib\tkinter\__init__.py", line 1533, in __call__
return self.func(*args)
File "C:\Python34\Lib\site-packages\matplotlib\backends\backend_tkagg.py", line 278, in resize
self.show()
File "C:\Python34\Lib\site-packages\matplotlib\backends\backend_tkagg.py", line 349, in draw
FigureCanvasAgg.draw(self)
File "C:\Python34\Lib\site-packages\matplotlib\backends\backend_agg.py", line 469, in draw
self.figure.draw(self.renderer)
File "C:\Python34\Lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\Lib\site-packages\matplotlib\figure.py", line 1085, in draw
func(*args)
File "C:\Python34\Lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\Lib\site-packages\matplotlib\axes\_base.py", line 2110, in draw
a.draw(renderer)
File "C:\Python34\Lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\Lib\site-packages\matplotlib\axis.py", line 1116, in draw
renderer)
File "C:\Python34\Lib\site-packages\matplotlib\axis.py", line 1065, in _get_tick_bboxes
extent = tick.label1.get_window_extent(renderer)
File "C:\Python34\Lib\site-packages\matplotlib\text.py", line 798, in get_window_extent
bbox, info, descent = self._get_layout(self._renderer)
File "C:\Python34\Lib\site-packages\matplotlib\text.py", line 311, in _get_layout
ismath=False)
File "C:\Python34\Lib\site-packages\matplotlib\backends\backend_agg.py", line 232, in get_text_width_height_descent
font = self._get_agg_font(prop)
File "C:\Python34\Lib\site-packages\matplotlib\backends\backend_agg.py", line 276, in _get_agg_font
fname = findfont(prop)
File "C:\Python34\Lib\site-packages\matplotlib\font_manager.py", line 1421, in findfont
font = fontManager.findfont(prop, **kw)
File "C:\Python34\Lib\site-packages\matplotlib\font_manager.py", line 1304, in findfont
_rebuild()
File "C:\Python34\Lib\site-packages\matplotlib\font_manager.py", line 1402, in _rebuild
pickle_dump(fontManager, _fmcache)
File "C:\Python34\Lib\site-packages\matplotlib\font_manager.py", line 952, in pickle_dump
with open(filename, 'wb') as fh:
PermissionError: [Errno 13] Permission denied: 'C:\\Users\\KARTHIK KC\\.matplotlib\\fontList.py3k.cache'

plotting datetime object in matplotlib

I have an array of datetime objects that is the following
dates = [datetime.datetime(1900, 1, 1, 10, 8, 14, 565000), datetime.datetime(1900, 1, 1, 10, 8, 35, 330000), datetime.datetime(1900, 1, 1, 10, 8, 43, 358000), datetime.datetime(1900, 1, 1, 10, 8, 52, 808000)]
I then tried converting the array to matplotlib suitable objects using dates = plt.dates.date2num(dates)
Then I tried to plot it against some values using ax1.plot_date(dates, datac)
but received errors as follows:
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python34\lib\tkinter\__init__.py", line 1487, in __call__
return self.func(*args)
File "C:\Python34\lib\site-packages\matplotlib\backends\backend_tkagg.py", line 278, in resize
self.show()
File "C:\Python34\lib\site-packages\matplotlib\backends\backend_tkagg.py", line 349, in draw
FigureCanvasAgg.draw(self)
File "C:\Python34\lib\site-packages\matplotlib\backends\backend_agg.py", line 461, in draw
self.figure.draw(self.renderer)
File "C:\Python34\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\lib\site-packages\matplotlib\figure.py", line 1079, in draw
func(*args)
File "C:\Python34\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\lib\site-packages\matplotlib\axes\_base.py", line 2092, in draw
a.draw(renderer)
File "C:\Python34\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "C:\Python34\lib\site-packages\matplotlib\axis.py", line 1103, in draw
ticks_to_draw = self._update_ticks(renderer)
File "C:\Python34\lib\site-packages\matplotlib\axis.py", line 957, in _update_ticks
tick_tups = [t for t in self.iter_ticks()]
File "C:\Python34\lib\site-packages\matplotlib\axis.py", line 957, in <listcomp>
tick_tups = [t for t in self.iter_ticks()]
File "C:\Python34\lib\site-packages\matplotlib\axis.py", line 905, in iter_ticks
for i, val in enumerate(majorLocs)]
File "C:\Python34\lib\site-packages\matplotlib\axis.py", line 905, in <listcomp>
for i, val in enumerate(majorLocs)]
File "C:\Python34\lib\site-packages\matplotlib\dates.py", line 580, in __call__
result = self._formatter(x, pos)
File "C:\Python34\lib\site-packages\matplotlib\dates.py", line 412, in __call__
return self.strftime(dt, self.fmt)
File "C:\Python34\lib\site-packages\matplotlib\dates.py", line 450, in strftime
s1 = time.strftime(fmt, (year,) + timetuple[1:])
ValueError: Invalid format string
Does anyone have any advice on how to fix this? Thanks in advance!

dates = plt.dates.date2num(dates)
is not appropriate as you would have used the following command
import matplotlib.pyplot as plt
So here plt does not contain date2num function. So you would have to use
from matplotlib.dates import date2num
and dates =date2num(dates).
I think this will work fine

Inexplicable bug in matplolib and numpy : "IndexError: string index out of range"

I am currently dealing with an inexplicable bug in python+matplotlib+numpy. I'm under Ubuntu 13.04 x64 in a VirtualBox hosted by Windows 7 pro x64 and I use python 2.7 (installed from the Ubuntu repositories).
Consider the following script that plots y as a function of x from a two column file named data.txt :
#!/usr/bin/env python
import numpy as np
import matplotlib as mpl
mpl.rcParams['text.usetex']=True
import matplotlib.pyplot as plt
x, y = np.loadtxt("data.txt", unpack=True)
plt.plot(x, y)
plt.show()
And consider the following data.txt :
-49.5938 2.0
-40.6585 0.156267
-39.7351 0.0616373
-39.1767 0.00565121
-38.7736 -0.0346863
-38.4573 -0.0664897
-38.1965 -0.0929013
-37.9744 -0.115588
-37.7809 -0.135542
-37.6093 -0.153403
-37.4551 -0.169605
-37.3151 -0.18446
-37.1868 -0.198198
-37.0684 -0.210994
-36.9584 -0.222983
-36.8722 -0.232458
-36.8228 -0.237918
-36.7749 -0.243232
-36.7284 -0.248409
-36.6833 -0.253457
-36.6395 -0.258382
-36.5968 -0.263192
-36.5553 -0.267892
-36.5149 -0.272489
-36.4754 -0.276987
-36.437 -0.281392
-36.3994 -0.285707
-36.3628 -0.289937
-36.3269 -0.294086
-36.2919 -0.298157
-36.2577 -0.302154
-36.2241 -0.30608
-36.1913 -0.309937
-36.1591 -0.313729
-36.1276 -0.317458
-36.0966 -0.321126
-36.0663 -0.324736
-36.0366 -0.32829
-36.0074 -0.33179
-35.9787 -0.335238
-35.9505 -0.338635
-35.9228 -0.341984
-35.8956 -0.345286
-35.8688 -0.348542
-35.8425 -0.351755
-35.8166 -0.354925
-35.7912 -0.358053
-35.7661 -0.361142
-35.7414 -0.364192
-35.7171 -0.367205
-35.6931 -0.37018
-35.6695 -0.373121
-35.6463 -0.376027
-35.6234 -0.378899
-35.6008 -0.381739
-35.5785 -0.384547
-35.5565 -0.387324
-35.5348 -0.390071
-35.5134 -0.392789
-35.4923 -0.395479
-35.4714 -0.39814
-35.4508 -0.400775
-35.4305 -0.403383
-35.4104 -0.405965
-35.3906 -0.408522
-35.371 -0.411054
-35.3517 -0.413563
-35.3326 -0.416047
-35.3137 -0.418509
-35.295 -0.420948
-35.2765 -0.423366
-35.2582 -0.425762
-35.2402 -0.428137
-35.2223 -0.430491
-35.2047 -0.432825
-35.1872 -0.43514
-35.1699 -0.437435
-35.1528 -0.439711
-35.1358 -0.44197
-35.119 -0.444212
-35.1024 -0.44644
-35.0859 -0.448658
-35.0694 -0.450878
-35.0529 -0.453105
-35.0363 -0.455341
-35.0195 -0.457613
-35.0024 -0.459933
-34.9849 -0.462312
-34.9669 -0.464766
-34.9483 -0.467309
-34.9292 -0.469936
-34.9092 -0.472681
-34.8886 -0.475519
-34.8672 -0.47848
-34.8449 -0.481569
-34.8219 -0.484767
-34.7982 -0.48807
-34.7739 -0.491477
-34.7491 -0.494958
-34.7241 -0.49848
-34.6992 -0.502011
-34.6742 -0.505551
-34.6495 -0.509079
-34.625 -0.512581
-34.6007 -0.516063
-34.5767 -0.519519
-34.553 -0.522941
-34.5296 -0.526332
-34.5065 -0.529692
-34.4837 -0.533017
-34.4612 -0.536311
-34.439 -0.539573
-34.4171 -0.542805
-34.3954 -0.546006
-34.374 -0.549176
-34.3529 -0.552316
-34.3321 -0.555427
-34.3115 -0.55851
-34.2912 -0.561564
-34.2711 -0.564591
-34.2512 -0.567592
-34.2316 -0.570566
-34.2121 -0.573515
-34.193 -0.576439
-34.174 -0.579339
-34.1552 -0.582214
-34.1367 -0.585066
-34.1183 -0.587895
-34.1002 -0.590701
-34.0822 -0.593485
-34.0644 -0.596248
-34.0468 -0.598989
-34.0294 -0.601709
-34.0122 -0.604409
-33.9951 -0.607089
-33.9783 -0.609748
-33.9615 -0.612389
-33.945 -0.615011
-33.9286 -0.617614
-33.9123 -0.620199
-33.8962 -0.622766
-33.8803 -0.625315
-33.8645 -0.627847
-33.8489 -0.630361
-33.8334 -0.632859
-33.818 -0.635341
-33.8028 -0.637806
-33.7877 -0.640256
-33.7727 -0.64269
-33.7579 -0.645108
-33.7432 -0.647511
-33.7286 -0.6499
-33.7141 -0.652274
-33.6998 -0.654634
-33.6856 -0.65698
-33.6714 -0.659315
-33.6574 -0.661635
-33.6435 -0.663947
-33.6297 -0.666249
-33.6159 -0.668547
-33.6022 -0.670835
-33.5885 -0.673127
-33.5749 -0.67542
-33.5612 -0.677726
-33.5475 -0.680025
-33.5338 -0.682341
-33.5201 -0.684666
-33.5062 -0.687017
-33.4923 -0.689387
-33.4782 -0.691796
-33.4639 -0.694247
-33.4494 -0.696723
-33.4347 -0.69924
-33.4199 -0.7018
-33.4047 -0.704414
-33.3893 -0.707087
-33.3737 -0.709791
-33.3578 -0.712549
-33.3418 -0.71534
-33.3255 -0.718181
-33.3091 -0.721056
-33.2924 -0.723999
-33.2755 -0.726975
-33.2585 -0.729988
-33.2412 -0.733045
-33.2237 -0.736152
-33.2061 -0.739295
-33.1884 -0.742461
-33.1706 -0.745656
-33.1525 -0.748904
-33.1344 -0.752172
-33.1162 -0.755459
-33.098 -0.758756
-33.0798 -0.762079
-33.0616 -0.765406
-33.0434 -0.768737
-33.0252 -0.772066
-33.0072 -0.775386
-32.9892 -0.778712
-32.9713 -0.78203
-32.9535 -0.785343
-32.9358 -0.788648
-32.9182 -0.791942
-32.9007 -0.795223
-32.8833 -0.798485
-32.8661 -0.801738
-32.8489 -0.804987
-32.8319 -0.808216
-32.8151 -0.811425
-32.7984 -0.814617
-32.7817 -0.817795
-32.7653 -0.82096
-32.7489 -0.824109
-32.7327 -0.82724
-32.7166 -0.830353
-32.7007 -0.833449
-32.6848 -0.83653
-32.6691 -0.839596
-32.6536 -0.842642
-32.6381 -0.845671
-32.6228 -0.848682
-32.6076 -0.85168
-32.5925 -0.854664
-32.5776 -0.857631
-32.5627 -0.860578
-32.548 -0.863512
-32.5334 -0.866433
-32.5189 -0.869332
-32.5046 -0.872219
-32.4903 -0.87509
-32.4761 -0.877949
-32.4621 -0.880793
-32.4481 -0.883619
-32.4343 -0.886435
-32.4205 -0.889237
-32.4069 -0.892021
-32.3934 -0.894796
-32.3799 -0.897551
-32.3666 -0.900292
-32.3534 -0.903023
-32.3402 -0.905737
-32.3272 -0.908445
-32.3142 -0.911134
-32.3013 -0.913813
-32.2885 -0.916482
-32.2759 -0.919132
-32.2633 -0.921769
-32.2507 -0.924401
-32.2383 -0.92702
-32.2259 -0.929628
-32.2136 -0.932223
-32.2015 -0.934805
-32.1893 -0.937376
-32.1773 -0.939932
-32.1654 -0.942481
-32.1535 -0.94502
-32.1417 -0.947543
-32.13 -0.950056
-32.1183 -0.95256
-32.1068 -0.955052
-32.0952 -0.957536
-32.0838 -0.960005
-32.0725 -0.962469
-32.0612 -0.964924
-32.0499 -0.967368
-32.0387 -0.969807
-32.0276 -0.972236
-32.0165 -0.974663
-32.0055 -0.977076
-31.9946 -0.979485
If I try to execute the script, I got the following error :
Exception in Tkinter callback
Traceback (most recent call last):
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1473, in __call__
return self.func(*args)
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_tkagg.py", line 276, in resize
self.show()
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_tkagg.py", line 348, in draw
FigureCanvasAgg.draw(self)
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_agg.py", line 440, in draw
self.figure.draw(self.renderer)
File "/usr/lib/pymodules/python2.7/matplotlib/artist.py", line 54, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/figure.py", line 1006, in draw
func(*args)
File "/usr/lib/pymodules/python2.7/matplotlib/artist.py", line 54, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 2086, in draw
a.draw(renderer)
File "/usr/lib/pymodules/python2.7/matplotlib/artist.py", line 54, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File "/usr/lib/pymodules/python2.7/matplotlib/axis.py", line 1052, in draw
renderer)
File "/usr/lib/pymodules/python2.7/matplotlib/axis.py", line 1001, in _get_tick_bboxes
extent = tick.label1.get_window_extent(renderer)
File "/usr/lib/pymodules/python2.7/matplotlib/text.py", line 752, in get_window_extent
bbox, info = self._get_layout(self._renderer)
File "/usr/lib/pymodules/python2.7/matplotlib/text.py", line 313, in _get_layout
ismath=ismath)
File "/usr/lib/pymodules/python2.7/matplotlib/backends/backend_agg.py", line 200, in get_text_width_height_descent
renderer=self)
File "/usr/lib/pymodules/python2.7/matplotlib/texmanager.py", line 606, in get_text_width_height_descent
page = next(iter(dvi))
File "/usr/lib/pymodules/python2.7/matplotlib/dviread.py", line 71, in __iter__
have_page = self._read()
File "/usr/lib/pymodules/python2.7/matplotlib/dviread.py", line 126, in _read
byte = ord(self.file.read(1)[0])
IndexError: string index out of range
The interesting thing, is that :
If I replace the two last values of the file by -32.0 -1.0 it works
If I remove mpl.rcParams['text.usetex']=True it also works
I would be very happy if one have any explanation about that very bizarre problem.