In order to remove all non-numeric characters from a string, replace() function is used. replace() Function: This function searches a string for a specific value, or a RegExp, and returns a new string where the replacement is done.
Python Remove Character from a String – How to Delete Characters from Strings. In Python you can use the replace() and translate() methods to specify which characters you want to remove from a string and return a new modified string result.
>>> import re
>>> re.sub("[^0-9]", "", "sdkjh987978asd098as0980a98sd")
'987978098098098'
Not sure if this is the most efficient way, but:
>>> ''.join(c for c in "abc123def456" if c.isdigit())
'123456'
The ''.join
part means to combine all the resulting characters together without any characters in between. Then the rest of it is a list comprehension, where (as you can probably guess) we only take the parts of the string that match the condition isdigit
.
This should work for both strings and unicode objects in Python2, and both strings and bytes in Python3:
# python <3.0
def only_numerics(seq):
return filter(type(seq).isdigit, seq)
# python ≥3.0
def only_numerics(seq):
seq_type= type(seq)
return seq_type().join(filter(seq_type.isdigit, seq))
@Ned Batchelder and @newacct provided the right answer, but ...
Just in case if you have comma(,) decimal(.) in your string:
import re
re.sub("[^\d\.]", "", "$1,999,888.77")
'1999888.77'
Just to add another option to the mix, there are several useful constants within the string
module. While more useful in other cases, they can be used here.
>>> from string import digits
>>> ''.join(c for c in "abc123def456" if c in digits)
'123456'
There are several constants in the module, including:
ascii_letters
(abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ)hexdigits
(0123456789abcdefABCDEF)If you are using these constants heavily, it can be worthwhile to covert them to a frozenset
. That enables O(1) lookups, rather than O(n), where n is the length of the constant for the original strings.
>>> digits = frozenset(digits)
>>> ''.join(c for c in "abc123def456" if c in digits)
'123456'
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