Does the character being replaced in .replace() have to be nonempty?

Question

In the context of this exercise, does the character being replaced in the .replace() method have to be nonempty?

Answer

No, the character being replaced in the .replace() method does not have to be a nonempty string, and can be the empty string ''.

When providing an empty string as the argument for the character to be replaced, this will essentially replace every part between characters in the string. One way you can look at this, is as though every nonempty character has two empty spaces around it, which can overlap with their adjacent characters.

Here is an example that might help to illustrate this more clearly

empty_string = ''
replaced = empty_string.replace('', '!!!')
print(replaced) # !!!

example_string = "code"
result = example_string.replace('', '==')
print(result) # ==c==o==d==e==
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Hello,

if in this example:

instead of '' we used ' ' as a character to be replaced, what would happen? Would it give us some kind of error because we don’t have any whitespaces in our string (“code”)?

Thank you.

If in s.replace(old, new), old is not present in s, the function simply returns s.

s1 = 'abc'
s2 = s1.replace('b', 'x')
s3 = s1.replace('z', 'x')
print(s2)
print(s3)

# Output:
axc
abc
4 Likes

Consider,

>>> 'code'.replace('', ' ')
' c o d e '
>>> 

As we can see there is a preponderance of empty strings through the string, code so the method does what it knows how to do. It replaces every instance with a space.

It does not know how to replace something that is not there so it simply ignores it and does nothing.

5 Likes