CODEWITHSUNDEEP
pythonmatplotlib
A_Matar
A_Matar

Reputation: 2320

matplotlib how to display axis values as strings not a range of floats

I wrote the following script to plot the frequencies of items in a python list. When the list is of strings, I am not able to display the actual string values on the x axis and I get this error:

Traceback (most recent call last):
  File "testy.py", line 15, in <module>
    plt.bar([row[0] for row in votes_count], [row[1] for row in votes_count])
  File "...\matplotlib\pyplot.py", line 2705, in bar
    **kwargs)
  File "....\matplotlib\__init__.py", line 1891, in inner
    return func(ax, *args, **kwargs)
  File "....\matplotlib\axes\_axes.py", line 2105, in bar
    left = [left[i] - width[i] / 2. for i in xrange(len(left))]
TypeError: unsupported operand type(s) for -: 'str' and 'float'

Here is the code:

from collections import Counter
import matplotlib.pyplot as plt
import plotly.plotly as py #pip install plotly 

votes = ['a','a','b','c','d']
tmp_votes_count = Counter (votes)
votes_count = []

for i in tmp_votes_count:
    votes_count.append ([i, tmp_votes_count[i]])


margin = 2
most_common_vote= [item for item in Counter(votes).most_common(1)]
plt.bar([row[0] for row in votes_count], [row[1] for row in votes_count])
plt.axis([0,4,0,most_common_vote[0][1]+margin])
plt.show()

Upvotes: 1

Views: 801

Answers (1)

vishes_shell
vishes_shell

Reputation: 23484

You firstly need to define axis as integers 

plt.bar(range(0, len(votes_count)), [row[1] for row in votes_count])

and then map them to actual str objects 

plt.xticks(range(0, len(votes_count)), [row[0] for row in votes_count])

Finally, 3 last refactored lines:

plt.bar(range(0, len(votes_count)), [row[1] for row in votes_count])
plt.xticks(range(0, len(votes_count)), [row[0] for row in votes_count])
plt.show()

Output: enter image description here

Upvotes: 2

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