I am new to Python and am wondering how to address the following attribute error. I believe I need to define/declare the file variable? Thanks for any suggestions, here is my script:
AttributeError Traceback (most recent call last)
in
51
52 # Write methods to print to Financial_Analysis_Summary
---> 53 file.write("Financial Analysis")
54 file.write("\n")
55 file.write("----------------------------")
AttributeError: 'str' object has no attribute 'write'
From your code and error, I think You've defined the variable 'file' as a string. Aslo there is no attribute write() in the class str. Hence, the reason for this error. For more information, include the whole script i.e., mainly the use of variable 'file'. I think you can use print() to print the above mentioned details or create a new class with a method inside to print your desired things
It looks like you've somehow defined file as a string rather than a file. What you should to is define it thus:
summary_file=open("C:/someFolder/someOtherFolder/Financial_Analysis_Summary.txt",
mode='r+', encoding='utf8')
and then write to it.
The first argument to the open function is the file path. The mode is how you want to access the file: 'r' lets you read the file and nothing else (and throws a FileNotFoundError if the file doesn't yet exist; the others just create it), 'r+' lets you write to the file while leaving its preexisting text in place (although if you write to the middle of the file you'll still overwrite whatever was there), 'w' deletes what was in the file and lets you write to it, 'a' lets you write text only to the end of the file, 'w+' and 'a+' are the same as w and a except they let you read from the file; you can add b to the end of any of these to interact with the file in the form of bytes rather than strings. The encoding should only matter if you plan to use Unicode characters, in which case set it to the same encoding you'll use to view the file (usually 'utf8') to avoid garbling non-ASCII characters.
Related
I am just learning about the text file function in python 3 by using website called, https://www.w3schools.com/python/python_file_write.asp and https://www.geeksforgeeks.org/reading-writing-text-files-python/ although the program seems collect, the text data in the python's programming screen doesn't show in the actual text data file.
Is there any mistake I've ever made in the text program below?
The version of my Python is Python 3.7.5 .
File = open("NewTextFile.Txt", "a")
string = "ABC"
File.write(string)
File.close
You forgot to put () at File.close, so the file is not properly closed. Try putting ().
Often it is recommended to use with clause:
with open('NewTextFile.Txt', 'a') as file:
string = 'ABC'
file.write(string)
Note that you don't need to explicitly close the file here. The file is kept open within the clause. Once your python program exits the with clause, the file is automatically closed; in this way your program gets less prone to mistakes.
For more information, see a relevant python doc:
It is good practice to use the with keyword when dealing with file objects. The advantage is that the file is properly closed after its suite finishes, even if an exception is raised at some point.
— https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files
I've been previously writing code for a quiz program with a text file that stores all of the participants' results. The code that converts the text file to a dictionary and the text file itself are shown below:
Code:
import collections
from collections import defaultdict
scores_guessed = collections.defaultdict(lambda: collections.deque(maxlen=4))
with open('GuessScores.txt') as f:
for line in f:
name,val = line.split(":")
scores_guessed[name].appendleft(int(val))
for k in sorted(scores_guessed):
print("\n"+k," ".join(map(str,scores_guessed[k])))
writer = open('GuessScores.txt', 'wb')
for key, value in scores_guessed.items():
output = "%s:%s\n" % (key,value)
writer.write(output)
The text file appears like this:
Jack:10
Dave:20
Adam:30
Jack:40
Adam:50
Dave:60
Jack:70
Dave:80
Jack:90
Jack:100
Dave:110
Dave:120
Adam:130
Adam:140
Adam:150
Now, when I run the program code, the dictionary appears like this:
Adam 150 140 130 50
Dave 120 110 80 60
Jack 100 90 70 40
Now, this arranges the dictionary into order of highest scores, and the top 4 scores!
I want the python IDLE to overwrite the GuessScores.txt to this:
Adam:150
Adam:140
Adam:130
Adam:50
Dave:120
Dave:110
Dave:80
Dave:60
Jack:100
Jack:90
Jack:70
Jack:40
BUT when I run the code, this error appears:
Traceback (most recent call last):
File "/Users/Ahmad/Desktop/Test Files SO copy/readFile_prompt.py", line 16, in <module>
writer.write(output)
TypeError: 'str' does not support the buffer interface
The GuessScores.txt file is empty because it cannot write to the file, since there is the error above.
Why is this happening? And what is the fix? I have asked this previously but there were numerous issues. I am running Python 3.3.2 on a Mac 10.8 Mavericks iMac, if that makes any help.
Thanks,
Delbert.
The first issue is that you are trying to write text to a file that you opened in binary mode. In 3.x, this will no longer work. "text" vs. "binary" used to mean very little (only affecting line-ending translation, so no difference at all on some systems). Now it means like what it sounds like: a file opened in text mode is one whose contents are to be treated like text with some specific encoding, and a file opened in binary mode is one whose contents are to be treated as a sequence of bytes.
Thus, you need open('GuessScores.txt', 'w'), not open('GuessScores.txt', 'wb').
That said, you really should be using with blocks to manage the files, and you're going to have to write code that actually formats the dictionary content in the way you want. I assume you intend to output in sorted name order, and you need to iterate over each deque and write a line for each item. Something like:
with open('GuessScores.txt', 'w') as f:
for name, scores in sorted(scores_guessed.items()):
for score in scores:
f.write("{}:{}\n".format(name, score))
(Note also the new-style formatting.)
If necessary, you can explicitly specify the encoding of the file in the open call, with the encoding keyword parameter. (If you don't know what I mean by "encoding", you must learn. I'm serious. Drop everything and look it up.)
The writing problem has to do with the b in your open function. You've opened it in binary mode, so only bytes can be written. You can either remove the b or call bytes on output to give it the right type. You have a logic error anyway though. When I run it on Python 2.7, the output to GuessedScores.txt is this:
Dave:deque([120,110,80,60],maxlen=4)
Jack:deque([100, 90, 70, 40], maxlen=4)
Adam:deque([150, 140, 130, 50], maxlen=4)
So your values are the whole deques, not the individual scores. You'll have to format them, similar to how you did in your print statement.
I would like to know a very basic thing of Python programming as I am a very basic programmer right now): how can I save a result (either a list, a string, or whatever) to a file in Python?
I've been searching a lot, but I couldn't find any good answer to this.
I was thinking about the ".write ()" method, but (for instance) it seems not working with strings, neither I know what it is supposed to do though.
So, my situation is that I have binary fils, which I would like to edit, therefore I found easy to convert them to strings, modify them, and now I'd like to save them i) back to binary files (jpegs images) and ii) in the folder I want.
How would I do that? Please I need some help.
UPDATE
Here is the script I'm trying to run:
import os, sys
newpath= r'C:/Users/Umberto/Desktop/temporary'
if not os.path.exists (newpath):
os.makedirs (newpath)
data= open ('C:/Users/Umberto/Desktop/Prove_Script/Varie/_BR_Browse.001_2065642654_1.BINARY', 'rb+')
edit_data= str (data.read () )
out_dir= os.path.join (newpath, 'feed', 'address')
data.close ()
# do my edits in a secon time...
edit_data.write (newpath)
edit_data.close ()
The error I get is:
AttributeError: 'str' object has no attribute 'write'
UPDATE_2
I tried to use pickle module to serialize my binary file, modify it and save it at the end, but still not getting it to work... This is what I've been trying so far:
import cPickle as pickle
binary= open ('C:\Users\Umberto\Desktop\Prove_Script\Varie\_BR_Browse.001_2065642654_1.BINARY', 'rb')
out= open ('C:\Users\Umberto\Desktop\Prove_Script\Varie\preview.txt', 'wb')
pickle.dump (binary, out, 1)
TypeError Traceback (most recent call last)
<ipython-input-6-981b17a6ad99> in <module>()
----> 1 pprint.pprint (pickle.dump (binary, out, 1))
C:\Python27\ArcGIS10.1\lib\copy_reg.pyc in _reduce_ex(self, proto)
68 else:
69 if base is self.__class__:
---> 70 raise TypeError, "can't pickle %s objects" % base.__name__
71 state = base(self)
72 args = (self.__class__, base, state)
TypeError: can't pickle file objects
Another thing I didn't get is that if I am supposed to create a file to poit to (in my case I had to create "out", otherwise I wouldn't have the right arguments for the pickle method) or it's not necessary.
Hope I'm getting close to the solution.
P.S.: I tried also with pickle.dumps (), not achieving a nicer result though...
If you're opening a binary file and saving another binary file you could do something like this:
with open('file.jpg', 'rb') as jpgFile:
contents = jpgFile.read()
contents = (some operations here)
with open('file2.jpg', 'wb') as jpgFile:
jpgFile.write(contents)
Some comments:
'rb' and 'wb' means read and write in binary mode respectively. More info on why 'b' is recommended when working with binary files here.
Python's with statement takes care of closing the file when exiting the block.
If you need to save lists, strings or other objects, and retrieving them later, use pickle as others pointed out.
You can use standard python module named "pickle".
You can read about it here: pickle documentation
Read and write any data structure will be very easy
pickle.dump(obj, file_handler) # for serialize object to file
pickle.load(file) # for deserialize from file
or you can serialize to string: pickle.dumps(..) and load from it: pickle.loads(...)
After reading some posts, it seems like you can open a file for both reading and writing with the mode of 'r+' or 'w+'. However, trying to use these modes always give me weird results:
If I use 'r+', call file.read(), and then call file.write('str'),
there'll be an error of "IOError: [Errno 0] Error"
If I use 'r+', call file.write('str'), and then call file.read(),
it'll return unexpected and very long content(looks like the inside
of some object)
If I use 'w+', calling file.read() will return empty string
What I'm trying to do is open a file, read the content, modify it, and write back. Currently I'm opening it with 'r', change the content, and open it again with 'w' and write back. Is this a good way of doing it?
There's an example at http://snipt.org/zglJ0
I'm using window 7 and python 2.7.2
You have to flush() when switching between reading and writing a file that's been opened in an update mode. Or I think you can also seek(). This is caused by some weird behavior in the Windows file implementation in Python 2.x; they fixed it in 3.x.
I am creating a program to read a FASTA file and split at some specifc characters such as '>' etc. But I'm facing a problem.
The program part is:
>>> def read_FASTA_strings(seq_fasta):
... with open(seq_fasta.txt) as file:
... return file.read().split('>')
The error:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'seq_fasta' is not defined
How to get rid of this problem?
You need to specify the file name as a string literal:
open('seq_fasta.txt')
You need to quote the filename: open('seq_fasta.txt').
Besides that, you might choose a different name but file as using this name shadows a builtin name.
Your program is seeing seq_fasta.txt as a object label, similar to how you would use math.pi after importing the math module.
This is not going to work because seq_fasta.txt doesnt actually point to anything, thus your error. What you need to do is either put quotes around it 'seq_fasta.txt' or create a text string object containing that and use that variable name in the open function. Because of the .txt it thinks seq_fasta(in the function header) and seq_fasta.txt(in the function body) are two different labels.
Next, you shouldnt use file as it is an important keyword for python and you could end up with some tricky bugs and a bad habit.
def read_FASTA_strings(somefile):
with open(somefile) as textf:
return textf.read().split('>')
and then to use it
lines = read_FASTA_strings("seq_fasta.txt")