Why won't my grouped box plot work in Python?

Question

I have a data set (my_data) that looks something like this:


Gender    Time     Money    Score

Female    23        14       26.74
Male      12        98       56.76
Male      11        34       53.98
Female    18        58       25.98

etc.

I want to make a grouped box plot of gender against score, so that there will be two plots in the same graph.

My code so far:

Males = [my_data.loc[my_data['Gender']=='Male', 'Score']]
Females = [my_data.loc[my_data['Gender']=='Female', 'Score']]

Score = [Males, Females]

fig, ax = plt.subplots()
ax.boxplot(Score)
plt.show()

However, this runs an error message:

ValueError: X must have 2 or fewer dimensions

I tried converting Males and Females to an array, thinking maybe Python wasn’t liking it as a list by doing:

Males = np.array([my_data.loc[my_data['Gender']=='Male', 'Score']])
Females = np.array([my_data.loc[my_data['Gender']=='Female', 'Score']])

But that still didn’t work. Also Python does say it takes lists as values for boxplots so I shouldn’t need to do that anyway.

I also tried a different way of making a boxplot like this:

fig = plt.figure(figsize =(10, 7))
 
ax = fig.add_axes([Males, Females])
 
bp = ax.boxplot(Score)

plt.show()

And it gave me this error code:

TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

<Figure size 720x504 with 0 Axes>

What’s going on?

Asked By: Rosie Jones

||

Source

Answer 1

When you extracted your source data, you put them unnecessary in square brackets.

Generate them instead as:

Males = my_data.loc[my_data['Gender']=='Male', 'Score']
Females = my_data.loc[my_data['Gender']=='Female', 'Score']

Then, to generate your box plot, you can run e.g.:

fig, ax = plt.subplots(1, 1)
ax.boxplot([Males, Females])
ax.set_xticklabels(['Males', 'Females'])
plt.show()

Answered By: Valdi_Bo

Why won't my grouped box plot work in Python?

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