Using Counter() in Python to build histogram?

Question

I saw on another question that I could use Counter() to count the number of occurrences in a set of strings. So if I have ['A','B','A','C','A','A'] I get Counter({'A':3,'B':1,'C':1}). But now, how can I use that information to build a histogram for example?

Answer 1

For your data it is probably better to use a barchart instead of a histogram. Check out this code:

from collections import Counter import numpy as np import matplotlib.pyplot as plt   labels, values = zip(*Counter(['A','B','A','C','A','A']).items())  indexes = np.arange(len(labels)) width = 1  plt.bar(indexes, values, width) plt.xticks(indexes + width * 0.5, labels) plt.show() 

Result:

Answer 2

You can write some really concise code to do this using pandas:

    import numpy as np      from pandas import Series          sample = np.random.choice(['a', 'b'], size=10)          s = Series(sample)          In [29]: s     Out[29]:     0    a     1    b     2    b     3    b     4    a     5    b     6    b     7    b     8    b     9    a     dtype: object          vc = s.value_counts()          In [31]: vc     Out[31]:     b    7     a    3     dtype: int64          vc = vc.sort_index()          In [33]: vc     Out[33]:     a    3     b    7     dtype: int64          c.plot(kind='bar') 

Resulting in: