How to use text strip() function?

Question

I can strip numerics but not alpha characters:

>>> text
'132abcd13232111'

>>> text.strip('123')
'abcd'

Why the following is not working?

>>> text.strip('abcd')
'132abcd13232111'

Answer 1

The reason is simple and stated in the documentation of strip:

str.strip([chars])

Return a copy of the string with the leading and trailing characters removed. 
The chars argument is a string specifying the set of characters to be removed.

'abcd' is neither leading nor trailing in the string '132abcd13232111' so it isn't stripped.

Answer 2

Just to add a few examples to Jim's answer, according to .strip() docs:

• Return a copy of the string with the leading and trailing characters removed.
• The chars argument is a string specifying the set of characters to be removed.
• If omitted or None, the chars argument defaults to removing whitespace.
• The chars argument is not a prefix or suffix; rather, all combinations of its values are stripped.

So it doesn't matter if it's a digit or not, the main reason your second code didn't worked as you expected, is because the term "abcd" was located in the middle of the string.

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Example1:

s = '132abcd13232111'
print(s.strip('123'))
print(s.strip('abcd'))

Output:

abcd
132abcd13232111

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Example2:

t = 'abcd12312313abcd'
print(t.strip('123'))
print(t.strip('abcd'))

Output:

abcd12312313abcd
12312313