We Keep Coding

How to plot a graph with matplotlib

Good evening, I am a student taking a required python course (completely new to coding) in Hong Kong.
I was asked to write a python program that shows a graph in an assignment, but I had encountered some difficulties.
I tried to follow some source codes I found on the internet, but it end up showing a bug-like page.
Can someone please kindly tell me which part of my code is wrong, how to correct it, and why is this resulting happening?
Also, I would like to ask that is there any difference between import as mpl and as plt?
source code:
import matplotlib as mpl
mpl.use('Agg')
import matplotlib.pyplot as plt
import numpy as np
xaxis = np.array([2,8])
yaxis = np.array([4,9])
plt.plot(xaxis, yaxis )
plt.show()
plt.savefig('table.png')
result:
bug-like result
Thank you all very much. Hope you have a nice day.

Using missing_kwds with geopandas changes the shape of the displayed map

I'm using Geopandas (0.11.1) to plot data on maps. I'm facing an issue with missing_kwds. As some of my values are undefined, I want them to be colored in a specific way. I do that using the missing_kwds option of the plot method.
However, when using it, the shape of the map slightly changes, which is disgraceful when switching quickly from one to the other.
Here is an example.
A map without using missing_kwds :
import geopandas
import matplotlib.pyplot as plt
df = geopandas.read_file(geopandas.datasets.get_path("naturalearth_lowres"))
df.plot()
plt.savefig('world1.png')
A map using missing_kwds :
import geopandas
import matplotlib.pyplot as plt
import numpy as np
df = geopandas.read_file(geopandas.datasets.get_path("naturalearth_lowres"))
df.loc[df.name=="China", 'pop_est'] = np.nan
df.plot(column="pop_est", missing_kwds=dict(color="lightgray"))
plt.savefig('world2.png')
Those are the two resulting maps.
world1.png:
world2.png:
In case the difference isn't clear, here is a GIF that illustrates the shape changes.
Does anyone have an idea how I could solve this issue?

Add plt.gca().set_aspect('equal') after df.plot().

My plot bar graph isn't showing up. What's wrong with my code

import matplotlib as mpl
import matplotlib.pyplot as plt
%matplotlib inline
%matplotlib notebook
plt.figure(figsize=(12, 6))
CasData.pivot(index='year', columns='CasualtyNumber', values='People').plot(kind='bar')
plt.title('Casualties per year')
plt.xlabel('Year', fontsize=5)
plt.ylabel('Number of Casualties')
plt.show()
My plot bar graph using matplotlib.pyplot isn't showing.
I don't know why but my bar graph isn't showing. I've tried different ways.
If someone could help me out please. I'd appreciate it. Thank you.

Remove the line %matplotlib notebook.
It is overriding the previous line (these two lines are setting the backend). inline returns static plots, notebook is used for interactivity.
You also do not need the plt.show() line. This is taken care of by the inline backend.
This answer explains more about the backends: https://stackoverflow.com/a/43028034/6709902

I'm not really sure about your code as it seems incomplete but if you're using pivot I assumed you're pulling the data from a ".csv" file.
import matplotlib as mpl
import matplotlib.pyplot as plt
import pandas as pd
%matplotlib notebook
CasData = pd.read_csv('data.csv')
CasData.pivot_table(index='year', columns='CasualtyNumber', values='People').plot(kind='bar')
plt.title('Casualties per year')
plt.xlabel('Year',fontsize='5')
plt.ylabel('Number of Casualties')
plt.show()
You need to provide the data in order to plot something and I don't
see you providing any.

box plot not appearing in Google Colab

Trying to create a simple Box Plot using Google Colab for my Intro Python class. It is not appearing as I would like it. You can see my code and output below. I read in a file on NBA statistics, and my box plot would be based on a variable called "SHOT_CLOCK".
So far what I have:
import pandas as pd
from matplotlib import pyplot as plt
df = pd.read_csv('file path')
plt.boxplot(df['SHOT_CLOCK'], vert=False)
plt.title('Box Plot for SHOT_CLOCK')
plt.xlabel('Shot Clock')
plt.show()
Output:

Edit
In your example you are passing a Series object, try this way
plt.figure()
plt.title('Box Plot for SHOT_CLOCK')
plt.xlabel('Shot Clock')
df.boxplot(column='SHOT_CLOCK')

Once you add the following Import to your code it will work:
import matplotlib.pyplot as plt
plt.style.use('classic')
%matplotlib inline

.plot() command does not display anything

I have this code based on this question, just a different point Extract constrained polygon using OSMnx
I am trying to plot the block in which the point is located but it does nothing, it just prints "Done" but I cannot see any image
import osmnx as ox
import geopandas as gpd
import shapely
point = (50.090464, 14.400070)
streets_graph = ox.graph_from_point(point, distance=500, network_type='drive')
streets_graph = ox.project_graph(streets_graph)
streets = ox.save_load.graph_to_gdfs(streets_graph, nodes=False, edges=True,
node_geometry=False, fill_edge_geometry=True)
point = streets.unary_union.centroid
polygons = shapely.ops.polygonize(streets.geometry)
polygons = gpd.GeoSeries(polygons)
target = polygons.loc[polygons.contains(point)]
target_streets = streets.loc[streets.intersection(target.iloc[0]).type == 'MultiLineString']
ax = target_streets.plot()
gpd.GeoSeries([point]).plot(ax=ax, color='r')
print("Done")
I do not think this may help but I am using Visual Studio Code
Thank you very much

Since my comment answered your question, I will summarize it here for other people:
When using plotting library dependent on matplotlib, like geopandas or seaborn, you will need to import matplotlib in order to show the plot. The way matplotlib is imported will depend on whether you are using Jupyter or simple scripting (.py) files.
For Jupyter you need to import it like this:
%matplotlib inline
For simple scripting (.py) file you need to import it like this:
import matplotlib.pyplot as plt
Then when you want to show your plot you simply do
plt.show()
Hope it helps!