Looping through a string

len( ) function

The len() function is a Python built-in function that reports the size, or length, of its input, which is usually a string or a list.

s = 'Apple pie'
print(len(s))                           # 9
print(len('Banana float'))              # 12

len('')                                 # 0 (an empty string)

print(len('donuts') + len('pan cake'))  # 14

Looping through a string

Here we show two ways to iterate over characters in a string:

Use the string index number to loop through the string

One way to iterate over a string is to use for i in range(len(str)):. In this loop, the variable i receives the index so that each character can be accessed using str[i].

Example:

t = 'World'

for i in range(len(t)):
    print(t[i])

Console result:

W
o
r
l
d

Directly loop through each item in the string

Another way to iterate over a string is to use for item in str:. The variable item receives the character directly so you do not have to use the index. Since this loop does not need the index value of each character, this loop format is simpler and is preferred over the previous one.

Example:

s = 'Buzz'

for char in s:
    print(char)

Console results:

B
u
z
z