Get the number of occurrences of each character

Question

Given the string:

a=\'dqdwqfwqfggqwq\'

How do I get the number of occurrences of each character?

Answer 1

lettercounts = {}
for letter in a:
    lettercounts[letter] = lettercounts.get(letter,0)+1

Answer 2

Not highly efficient, but it is one-line...

In [24]: a='dqdwqfwqfggqwq'

In [25]: dict((letter,a.count(letter)) for letter in set(a))
Out[25]: {'d': 2, 'f': 2, 'g': 2, 'q': 5, 'w': 3}

Answer 3

You can do this:

listOfCharac={}
for s in a:
    if s in listOfCharac.keys():
        listOfCharac[s]+=1
    else:
        listOfCharac[s]=1
print (listOfCharac)

Output {'d': 2, 'f': 2, 'g': 2, 'q': 5, 'w': 3}

This method is efficient as well and is tested for python3.

Answer 4

(For future reference)

This performance comparison of various approaches might be of interest.

Answer 5

For each letter count the difference between string with that letter and without it, that way you can get it's number of occurences

a="fjfdsjmvcxklfmds3232dsfdsm"
dict(map(lambda letter:(letter,len(a)-len(a.replace(letter,''))),a))

Answer 6

one line code for finding occurrence of each character in string.

for i in set(a):print('%s count is %d'%(i,a.count(i)))