Removing a prefix from a string [duplicate]

No. Stripping removes all characters in the sequence passed, not just the literal sequence. Slice the string if you want to remove a fixed length.

In Python 3.9 you can use bbn.removeprefix('0b1').

(Actually this question has been mentioned as part of the rationale in PEP 616.)

This is the way lstrip works. It removes any of the characters in the parameter, not necessarily the string as a whole. In the first example, since the input consisted of only those characters, nothing was left.

Lstrip is removing any of the characters in the string. So, as well as the initial 0b1, it is removing all zeros and all ones. Hence it is all gone!

@Harryooo: lstrip only takes the characters off the left hand end. So, because there's only one 1 before the first 0, it removes that. If the number started 0b11100101..., calling a.strip('0b').strip('1') would remove the first three ones, so you'd be left with 00101.

>>> i = 0b1000101110100010111010001
>>> print(bin(i))
'0b1000101110100010111010001'
>>> print(format(i, '#b'))
'0b1000101110100010111010001'
>>> print(format(i, 'b'))
'1000101110100010111010001'

See Example in python tutor:

From the standard doucmentation (See standard documentation for function bin()): bin(x) Convert an integer number to a binary string prefixed with “0b”. The result is a valid Python expression. If x is not a Python int object, it has to define an index() method that returns an integer. Some examples:

>>> bin(3)
'0b11'
>>> bin(-10)
'-0b1010'

If prefix “0b” is desired or not, you can use either of the following ways.

>>> format(14, '#b'), format(14, 'b')
('0b1110', '1110')
>>> f'{14:#b}', f'{14:b}'
('0b1110', '1110')

See also format() for more information.