It is also possible to loop over the characters of a string. The general form of a for loop over a string is as follows:
| | for variable in str: |
| | block |
As with a for loop over a list, the loop variable gets assigned a new value at the beginning of each iteration. In the case of a loop over a string, the variable is assigned a single character.
For example, we can loop over each character in a string, printing the uppercase letters:
| | >>> country = 'United States of America' |
| | >>> for ch in country: |
| | ... if ch.isupper(): |
| | ... print(ch) |
| | ... |
| | U |
| | S |
| | A |
In the previous code, variable ch is assigned country[0] before the first iteration, country[1] before the second, and so on. The loop iterates twenty-four times (once per character) and the if statement block is executed three times (once per uppercase letter).