Python - Avoid Spaces in string length

When working with strings in Python, we may sometimes need to calculate the length of a string excluding spaces. The presence of spaces can skew the length when we're only interested in the number of non-space characters. Let's explore different methods to find the length of a string while ignoring spaces.

Using replace()

replace() function allows us to remove all spaces from the string before calculating the length. This method is simple and efficient for removing spaces and counting the characters left.

s = "geeks for geeks"
res = len(s.replace(" ", ""))
print(res) 

13

Explanation:

• We use the replace() function to remove all spaces in the string by replacing them with an empty string.
• Then, we use len() to calculate the length of the string without spaces.

Let's explore some more methods and see how we can avoid spaces in string length.

Using for loop

We can also iterate over the string and count each character that is not a space. This method gives us more control over the process but requires more code.

s = "geeks for geeks"
res = 0
for c in s:
    if c != " ":
        res += 1
print(res)  

13

Explanation:

• We initialize the result variable res to 0.
• The for loop iterates over each character in the string, and if the character is not a space, we increment the res variable.

Using list comprehension

A more concise approach involves using list comprehension to filter out spaces and then using the len() function to get the length of the resulting list.

s = "geeks for geeks"
res = len([c for c in s if c != " "])
print(res)  

13

Explanation:

• A list comprehension is used to generate a list of characters that are not spaces.
• We then calculate the length of this list using len().

Using filter()

The filter() function is another way to remove spaces from the string before calculating the length. It allows us to filter out non-space characters and then use len() to count them.

s = "geeks for geeks"
res = len(list(filter(lambda c: c != " ", s)))
print(res)  

13

Explanation:

• We use filter() with a lambda function to filter out spaces from the string.
• The resulting filter object is converted to a list, and we then use len() to find its length.
• This method is functional but less efficient than using replace().

Using regular expressions

We can use the re.sub() function to remove all spaces before calculating the length.

import re
s = "geeks for geeks"
res = len(re.sub(r" ", "", s))
print(res)  

13

Explanation:

• We use the re.sub() function to replace all spaces with an empty string.
• Then, we calculate the length of the resulting string using len().