Question

I am a beginner struggling with Python every day. I have a large data set that has Name of animals in the 2nd column. I have a program to add up the count of each animal by its name (each row has 1 animal Name and 1 “count” data). I am trying to get the sum of those count data I obtained using Python but I am not being able to do that. The code I have so far is:

import csv, collections

reader=csv.reader(open('C:\Users\Owl\Data.txt','rb'), delimiter='\t')

counts=collections.Counter()

for line in reader:
   Name=line[1]
   counts[Name]+=1

for (Name, count) in sorted(counts.iteritems()):
   Output=list('%s' % count) #Make output string to a list
   Sum=sum(Output) # Sum function requires a list
   print 'Total kinds of Animals: %s' % Sum

I get an error saying " File "sum_count.py", line 17, in <module> Sum=sum(Output) # Sum function requires a list TypeError: unsupported operand type(s) for +: 'int' and 'str'".

What I have figured out so far is that because sum apparently require the input type to be a list, I converted the count data (which was string) to a list but when I do Output=list('%s' % count), it seems that all the count data that are more than 2 digits are split. For example, when I print Output, it will be like this:

['1', '6', '3']
['3']
['1', '8', '5', '9']
['7', '9']

instead of

['163']
['3']
['1859']
['79']

What I want to do here is to get a single “sum” of these elements. Here, it will be 4. Four kinds of animals.

I am thinking that this may be the reason why I am getting the error above. I might be wrong but could somebody please help me how to solve this issue? Thank you for your help in advance!

Answer 1

I don’t think you need to use sum.

Try this:

for (Name, count) in sorted(counts.iteritems()):
    print 'Species total: %s' % count

Or, possibly better:

for (Name, count) in sorted(counts.iteritems()):
    print 'Total for species %s: %s' % (Name, count)

sum is for when you have a list of numbers and want to find the sum of that list of numbers.
You have already collected the sum number of each animal using counts — you just need to display it.

Edit

To sum up the total number of animals counted, you can do this:

total = sum(counts.values())
print 'Total number of animals: %d' % total

Edit 2

The number of kinds of animals counted is simply the length of the counts dictionary:

print 'Number of kinds of animals: %d' % len(counts)