将 Python substring 与 char 值进行比较

Question

I'm trying to iterate through a loop in Python and compare the current char on a string, with a constant char.

for i in s:
        if(s[i]=='I')
            mySum++
            

This code gives me a syntax error on the if statement.

The same code in Java would look something like this

for(int i = 0; i<s.length();i++)
{
     if(s.charAt(i)=='I')
         {
          mySum++
         }
}

How do I do this in Python?

Answer 1

Use += 1 in python:

for i in s:
    if i == 'I':
        mySum += 1

Also add a colon after if .

Answer 2

Just like @U12-Forward suggested, there is no ++ operator in python. So you'll have you use the += operator.

However, I prefer @Iain answer rather.

my_sum = s.count('I')

Answer 3

Problem is not in if(s[i]=='I') , the problem is in: mySum++ .

Python do not support ++ operator. You can do it by following ways:

mySum++ --> mySum +=1

## Or

mySum++ --> mySum = mySum + 1