Removing a prefix from a string

The strip family treat the arg as a set of characters to be removed. The default set is "all whitespace characters".

You want:

if strg.startswith("0b1"):
   strg = strg[3:]

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.)