What is the difference between codes in line 4 in the following two programs? The first one prints 5 but the second one prints 15

Question

s = "azcbobobegghakl"
count = 0
for char in s:
    if char == 'a' or char== 'e' or char== 'i' or char== 'o' or char== 'u':
        count += 1
print count


s = "azcbobobegghakl"
count = 0
for char in s:
    if char == 'a' or 'e' or 'i' or 'o' or 'u':
        count += 1
print count

Answer 1

Non-empty strings will evaluate to True, therefore or 'a' will be the same as doing or True:

>>> bool('a')
True

>>> bool('')
False

If you wanted to count the vowels, then you could use regular expressions:

import re

s = "azcbobobegghakl"
l = re.findall('[aeiou]', s)
print(len(l))

# Returns: 5

Answer 2

char == 'a' or 'e' or 'i' or 'o' or 'u' will evaluate as (((((char == 'a') or 'e') or 'i') or 'o') or 'u'). Since any string other than the empty string will evaluate to True, your expression is the same as evaluating char == 'a' or True, which will be always True.