Making a histogram of string values in python

Question

OK so I have six possible values for data to be which are '32', '22', '12', '31', '21' and '11'. I have these stored as strings. Is it possible for python to sort through the data and just make six bins and show how many of each I have? Or do the inputs to a histogram HAVE to be numerical?

There is a difference between a bar graph and a histogram. A bar graph is appropriate here, while a histogram is not. — Waleed Khan
– Waleed Khan, Commented Oct 31, 2012 at 11:17
OK but if I used a bar graph would I have to manually sort through each piece of data to determine which category it was in before plotting? Is there a way of getting it to sort it for me like the histogram does? — Catherine Georgia
– Catherine Georgia, Commented Oct 31, 2012 at 11:19
What do you mean by "like the histogram does"? Is there a Python histogram library I don't know about? — Waleed Khan
– Waleed Khan, Commented Oct 31, 2012 at 11:22
If you have a list of strs you can convert them to ints fairly easily: listOfInts = map(int,listOfStrs) — Matt
– Matt, Commented Oct 31, 2012 at 11:44
Check this post: stackoverflow.com/questions/7871338/… after following Matts advice (converting all to ints). — user648129
– user648129, Commented Oct 31, 2012 at 11:49

user647772 · Accepted Answer · 2012-10-31 11:48:55Z

15

data =  ['32', '22', '12', '32', '22', '12', '31', '21', '11']
dict((x, data.count(x)) for x in data)

Result

{'11': 1, '12': 2, '21': 1, '22': 2, '31': 1, '32': 2}

answered Oct 31, 2012 at 11:48

user647772

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Comments

GilZ · Accepted Answer · 2012-10-31 12:30:45Z

8

Did you consider using collections.Counter?

# python 2.7
>>> l = ['32', '22', '12', '31', '21', '11', '32']
>>> import collections
>>> collections.Counter(l)
Counter({'32': 2, '11': 1, '12': 1, '21': 1, '22': 1, '31': 1})

answered Oct 31, 2012 at 12:30

GilZ

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1 Comment

Catherine Georgia Over a year ago

Thanks, this looks like it would be super useful but sadly I seem to be on Python 2.6.6.

f p · Accepted Answer · 2012-10-31 11:46:21Z

2

data =  ['32', '22', '12', '32', '22', '12', '31', '21', '11']
sm = {i:0 for i in ['32', '22', '12', '31', '21','11']}
for i in data:
    sm[i] += 1
print sm

Something like this?

answered Oct 31, 2012 at 11:46

f p

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Comments

Community · Accepted Answer · 2017-05-23 12:02:02Z

0

Assuming data is a list and you want to count the numbers in a bins. I will use bins as a dictionary.

bin = {'11': 0, '12': 0, '21': 0, '22': 0, '31': 0, '32': 0}

for element in data:
    if element in bin:  # Ignore other elements in data if any
        bin[element] = bin[element] + 1

bins dictionary will have frequency of each element in data list. Now you can use bins to plot bar graph using graph plot library. May be you can use this post to check matplotlib usage for plotting bar graph.

edited May 23, 2017 at 12:02

CommunityBot

11 silver badge

answered Oct 31, 2012 at 11:53

user648129

5 Comments

user647772 Over a year ago

List comprehension is Pythonic, explicit looping is not.

user647772 Over a year ago

People are confused about what is pythonic - it means "easy to write, read and understand in Python" or "idiomatic Python". Your code is idiomatic C/Java/...

user648129 Over a year ago

And you claim that this code doesn't obey this definition is wrong.

user648129 Over a year ago

I wouldn't discuss this further. But I disagree with your claim. Thank you.

user647772 Over a year ago

Also see stackoverflow.com/questions/58968/…

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