问题
Is there a Python function that will trim whitespace (spaces and tabs) from a string?
Example: \\t example string\\t → example string
回答1:
Whitespace on both sides:
s = " \t a string example\t "
s = s.strip()
Whitespace on the right side:
s = s.rstrip()
Whitespace on the left side:
s = s.lstrip()
As thedz points out, you can provide an argument to strip arbitrary characters to any of these functions like this:
s = s.strip(' \t\n\r')
This will strip any space, \t, \n, or \r characters from the left-hand side, right-hand side, or both sides of the string.
The examples above only remove strings from the left-hand and right-hand sides of strings. If you want to also remove characters from the middle of a string, try re.sub:
import re
print re.sub('[\s+]', '', s)
That should print out:
astringexample
回答2:
Python trim method is called strip:
str.strip() #trim
str.lstrip() #ltrim
str.rstrip() #rtrim
回答3:
For leading and trailing whitespace:
s = ' foo \t '
print s.strip() # prints "foo"
Otherwise, a regular expression works:
import re
pat = re.compile(r'\s+')
s = ' \t foo \t bar \t '
print pat.sub('', s) # prints "foobar"
回答4:
You can also use very simple, and basic function: str.replace(), works with the whitespaces and tabs:
>>> whitespaces = " abcd ef gh ijkl "
>>> tabs = " abcde fgh ijkl"
>>> print whitespaces.replace(" ", "")
abcdefghijkl
>>> print tabs.replace(" ", "")
abcdefghijkl
Simple and easy.
回答5:
#how to trim a multi line string or a file
s=""" line one
\tline two\t
line three """
#line1 starts with a space, #2 starts and ends with a tab, #3 ends with a space.
s1=s.splitlines()
print s1
[' line one', '\tline two\t', 'line three ']
print [i.strip() for i in s1]
['line one', 'line two', 'line three']
#more details:
#we could also have used a forloop from the begining:
for line in s.splitlines():
line=line.strip()
process(line)
#we could also be reading a file line by line.. e.g. my_file=open(filename), or with open(filename) as myfile:
for line in my_file:
line=line.strip()
process(line)
#moot point: note splitlines() removed the newline characters, we can keep them by passing True:
#although split() will then remove them anyway..
s2=s.splitlines(True)
print s2
[' line one\n', '\tline two\t\n', 'line three ']
回答6:
No one has posted these regex solutions yet.
Matching:
>>> import re
>>> p=re.compile('\\s*(.*\\S)?\\s*')
>>> m=p.match(' \t blah ')
>>> m.group(1)
'blah'
>>> m=p.match(' \tbl ah \t ')
>>> m.group(1)
'bl ah'
>>> m=p.match(' \t ')
>>> print m.group(1)
None
Searching (you have to handle the "only spaces" input case differently):
>>> p1=re.compile('\\S.*\\S')
>>> m=p1.search(' \tblah \t ')
>>> m.group()
'blah'
>>> m=p1.search(' \tbl ah \t ')
>>> m.group()
'bl ah'
>>> m=p1.search(' \t ')
>>> m.group()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'group'
If you use re.sub, you may remove inner whitespace, which could be undesirable.
回答7:
Whitespace includes space, tabs and CRLF. So an elegant and one-liner string function we can use is translate.
' hello apple'.translate(None, ' \n\t\r')
OR if you want to be thorough
import string
' hello apple'.translate(None, string.whitespace)
回答8:
(re.sub(' +', ' ',(my_str.replace('\n',' ')))).strip()
This will remove all the unwanted spaces and newline characters. Hope this help
import re
my_str = ' a b \n c '
formatted_str = (re.sub(' +', ' ',(my_str.replace('\n',' ')))).strip()
This will result :
' a b \n c ' will be changed to 'a b c'
回答9:
something = "\t please_ \t remove_ all_ \n\n\n\nwhitespaces\n\t "
something = "".join(something.split())
output:
please_remove_all_whitespaces
Adding Le Droid's comment to the answer. To separate with a space:
something = "\t please \t remove all extra \n\n\n\nwhitespaces\n\t "
something = " ".join(something.split())
output:
please remove all extra whitespaces
回答10:
If using Python 3: In your print statement, finish with sep="". That will separate out all of the spaces.
EXAMPLE:
txt="potatoes"
print("I love ",txt,"",sep="")
This will print: I love potatoes.
Instead of: I love potatoes .
In your case, since you would be trying to get ride of the \t, do sep="\t"
回答11:
try translate
>>> import string
>>> print '\t\r\n hello \r\n world \t\r\n'
hello
world
>>> tr = string.maketrans(string.whitespace, ' '*len(string.whitespace))
>>> '\t\r\n hello \r\n world \t\r\n'.translate(tr)
' hello world '
>>> '\t\r\n hello \r\n world \t\r\n'.translate(tr).replace(' ', '')
'helloworld'
回答12:
If you want to trim the whitespace off just the beginning and end of the string, you can do something like this:
some_string = " Hello, world!\n "
new_string = some_string.strip()
# new_string is now "Hello, world!"
This works a lot like Qt's QString::trimmed() method, in that it removes leading and trailing whitespace, while leaving internal whitespace alone.
But if you'd like something like Qt's QString::simplified() method which not only removes leading and trailing whitespace, but also "squishes" all consecutive internal whitespace to one space character, you can use a combination of .split() and " ".join, like this:
some_string = "\t Hello, \n\t world!\n "
new_string = " ".join(some_string.split())
# new_string is now "Hello, world!"
In this last example, each sequence of internal whitespace replaced with a single space, while still trimming the whitespace off the start and end of the string.
回答13:
Generally, I am using the following method:
>>> myStr = "Hi\n Stack Over \r flow!"
>>> charList = [u"\u005Cn",u"\u005Cr",u"\u005Ct"]
>>> import re
>>> for i in charList:
myStr = re.sub(i, r"", myStr)
>>> myStr
'Hi Stack Over flow'
Note: This is only for removing "\n", "\r" and "\t" only. It does not remove extra spaces.
回答14:
for removing whitespaces from the middle of the string
$p = "ATGCGAC ACGATCGACC";
$p =~ s/\s//g;
print $p;
output:
ATGCGACACGATCGACC
回答15:
This will remove all whitespace and newlines from both the beginning and end of a string:
>>> s = " \n\t \n some \n text \n "
>>> re.sub("^\s+|\s+$", "", s)
>>> "some \n text"
来源：https://stackoverflow.com/questions/1185524/how-do-i-trim-whitespace