How do I trim whitespace?

Just one space or all consecutive spaces? If the second, then strings already have a .strip() method:

>>> " Hello ".strip()
"Hello"
>>> " Hello".strip()
"Hello"
>>> "Bob has a cat".strip()
"Bob has a cat"
>>> "   Hello   ".strip()  # ALL consecutive spaces at both ends removed
"Hello"

If you only need to remove one space however, you could do it with:

def strip_one_space(s):
    if s.endswith(" "): s = s[:-1]
    if s.startswith(" "): s = s[1:]
    return s

>>> strip_one_space("   Hello ")
"  Hello"

Also, note that str.strip() removes other whitespace characters as well (e.g. tabs and newlines). To remove only spaces, you can specify the character to remove as an argument to strip, i.e.:

>>> "  Hello
".strip(" ")
"Hello
"

As pointed out in answers above

my_string.strip()

will remove all the leading and trailing whitespace characters such as , , , f, space .

For more flexibility use the following

• Removes only leading whitespace chars: my_string.lstrip()
• Removes only trailing whitespace chars: my_string.rstrip()
• Removes specific whitespace chars: my_string.strip(" ") or my_string.lstrip(" ") or my_string.rstrip(" ") and so on.

More details are available in the docs.

For whitespace on both sides use str.strip:

s = "  	 a string example	  "
s = s.strip()

For whitespace on the right side use rstrip:

s = s.rstrip()

For whitespace on the left side lstrip:

s = s.lstrip()

As thedz points out, you can provide an argument to strip arbitrary characters to any of these functions like this:

s = s.strip(" 	

")

This will strip any space, , , or characters from the left-hand side, right-hand side, or both sides of the string.

The examples above only remove strings from the left-hand and right-hand sides of strings. If you want to also remove characters from the middle of a string, try re.sub:

import re
print(re.sub("[s+]", "", s))

That should print out:

astringexample