Replace multiple spaces of a string with one space in Python

How can we replace multiple spaces of a string with one space in Python? Using the replace() as follows is incorrect.

s = 'it   is  an  apple    .'

t = s.replace('  ', ' ')

print(t)  # it  is an apple  .

Replacing two spaces with one space doesn't replace four spaces with one space so there are two spaces between it and is. The simplest way to convert multiple spaces to one space is splitting a string by a space and concatenating words with a space.

s = '  it is  an  apple  . '

a = s.strip()
b = ' '.join(s.split())

print(a)  # it is  an  apple  .
print(b)  # it is an apple .

Note that the strip() removes leading and trailing spaces. The split() splits a string by one space into a list of words.

s = '  it is  an  apple  . '

x = s.split()
b = ' '.join(x)

print(x)  # ['it', 'is', 'an', 'apple', '.']
print(b)  # it is an apple .

The join() is a string method that concatenates all the elements in a list. In this case, (one space) is a "glue" of it.