I see many questions asking how to remove leading zeroes from a string, but I have not seen any that ask how to remove any and all leading digits from a string.
I have been experimenting with combinations of lstrip, type function, isdigit, slice notation and regex without yet finding a method.
Is there a simple way to do this?
For example:
A simple way could be to denote all digits with string.digits, which quite simply provides you with a string containing all digit characters '0123456789' to remove with string.lstrip.
>>> from string import digits
>>> s = '123dog12'
>>> s.lstrip(digits)
'dog12'
I want to point out that though both Mitch and RebelWithoutAPulse's answer are correct, they do not do the same thing.
Mitch's answer left-strips any characters in the set '1', '2', '3', '4', '5', '6', '7', '8', '9', '0'.
>>> from string import digits
>>> digits
'0123456789'
>>> '123dog12'.lstrip(digits)
'dog12'
RevelWithoutAPulse's answern on the other hand, left-strips any character known to be a digit.
>>> import re
>>> re.sub('^\d+', '', '123dog12')
'dog12'
So what's the difference? Well, there are two differences:
lstrip is ambiguous on RTL languages. Actually, it removes leading matching characters, which may be on the right side. Regexp's ^ operator is more straightforward about it.Here are a few examples:
>>> '١٩٨٤فوبار٤٢'.lstrip(digits)
'١٩٨٤فوبار٤٢'
>>> re.sub('^\d+', '', '١٩٨٤فوبار٤٢')
'فوبار٤٢'
>>> '𝟏𝟗𝟖𝟒foobar𝟒𝟐'.lstrip(digits)
'𝟏𝟗𝟖𝟒foobar𝟒𝟐'
>>> re.sub('^\d+', '', '𝟏𝟗𝟖𝟒foobar𝟒𝟐')
'foobar𝟒𝟐'
(note for the Arabic example, Arabic being read from right to left, it is correct for the number on the right to be removed)
So… I guess the conclusion is be sure to pick the right solution depending on what you're trying to do.
Using regexes from re:
import re
re.sub('^\d+', '', '1234AB456')
Becomes:
'AB456'
replaces any positive amount of digits at the beginning of the string with empty string.
