This question already has answers here:
How can I put an actual backslash in a string literal (not use it for an escape sequence)?
(4 answers)
Closed 7 months ago.
In python, I am trying to replace a single backslash ("\") with a double backslash("\"). I have the following code:
directory = string.replace("C:\Users\Josh\Desktop\20130216", "\", "\\")
However, this gives an error message saying it doesn't like the double backslash. Can anyone help?
No need to use str.replace or string.replace here, just convert that string to a raw string:
>>> strs = r"C:\Users\Josh\Desktop\20130216"
^
|
notice the 'r'
Below is the repr version of the above string, that's why you're seeing \\ here.
But, in fact the actual string contains just '\' not \\.
>>> strs
'C:\\Users\\Josh\\Desktop\\20130216'
>>> s = r"f\o"
>>> s #repr representation
'f\\o'
>>> len(s) #length is 3, as there's only one `'\'`
3
But when you're going to print this string you'll not get '\\' in the output.
>>> print strs
C:\Users\Josh\Desktop\20130216
If you want the string to show '\\' during print then use str.replace:
>>> new_strs = strs.replace('\\','\\\\')
>>> print new_strs
C:\\Users\\Josh\\Desktop\\20130216
repr version will now show \\\\:
>>> new_strs
'C:\\\\Users\\\\Josh\\\\Desktop\\\\20130216'
Let me make it simple and clear. Lets use the re module in python to escape the special characters.
Python script :
import re
s = "C:\Users\Josh\Desktop"
print s
print re.escape(s)
Output :
C:\Users\Josh\Desktop
C:\\Users\\Josh\\Desktop
Explanation :
Now observe that re.escape function on escaping the special chars in the given string we able to add an other backslash before each backslash, and finally the output results in a double backslash, the desired output.
Hope this helps you.
Use escape characters: "full\\path\\here", "\\" and "\\\\"
In python \ (backslash) is used as an escape character. What this means that in places where you wish to insert a special character (such as newline), you would use the backslash and another character (\n for newline)
With your example string you would notice that when you put "C:\Users\Josh\Desktop\20130216" in the repl you will get "C:\\Users\\Josh\\Desktop\x8130216". This is because \2 has a special meaning in a python string. If you wish to specify \ then you need to put two \\ in your string.
"C:\\Users\\Josh\\Desktop\\28130216"
The other option is to notify python that your entire string must NOT use \ as an escape character by pre-pending the string with r
r"C:\Users\Josh\Desktop\20130216"
This is a "raw" string, and very useful in situations where you need to use lots of backslashes such as with regular expression strings.
In case you still wish to replace that single \ with \\ you would then use:
directory = string.replace(r"C:\Users\Josh\Desktop\20130216", "\\", "\\\\")
Notice that I am not using r' in the last two strings above. This is because, when you use the r' form of strings you cannot end that string with a single \
Why can't Python's raw string literals end with a single backslash?
https://pythonconquerstheuniverse.wordpress.com/2008/06/04/gotcha-%E2%80%94-backslashes-are-escape-characters/
Maybe a syntax error in your case,
you may change the line to:
directory = str(r"C:\Users\Josh\Desktop\20130216").replace('\\','\\\\')
which give you the right following output:
C:\\Users\\Josh\\Desktop\\20130216
The backslash indicates a special escape character. Therefore, directory = path_to_directory.replace("\", "\\") would cause Python to think that the first argument to replace didn't end until the starting quotation of the second argument since it understood the ending quotation as an escape character.
directory=path_to_directory.replace("\\","\\\\")
Given the source string, manipulation with os.path might make more sense, but here's a string solution;
>>> s=r"C:\Users\Josh\Desktop\\20130216"
>>> '\\\\'.join(filter(bool, s.split('\\')))
'C:\\\\Users\\\\Josh\\\\Desktop\\\\20130216'
Note that split treats the \\ in the source string as a delimited empty string. Using filter gets rid of those empty strings so join won't double the already doubled backslashes. Unfortunately, if you have 3 or more, they get reduced to doubled backslashes, but I don't think that hurts you in a windows path expression.
You could use
os.path.abspath(path_with_backlash)
it returns the path with \
Use:
string.replace(r"C:\Users\Josh\Desktop\20130216", "\\", "\\")
Escape the \ character.
Related
When I write print('\') or print("\") or print("'\'"), Python doesn't print the backslash \ symbol. Instead it errors for the first two and prints '' for the third. What should I do to print a backslash?
This question is about producing a string that has a single backslash in it. This is particularly tricky because it cannot be done with raw strings. For the related question about why such a string is represented with two backslashes, see Why do backslashes appear twice?. For including literal backslashes in other strings, see using backslash in python (not to escape).
You need to escape your backslash by preceding it with, yes, another backslash:
print("\\")
And for versions prior to Python 3:
print "\\"
The \ character is called an escape character, which interprets the character following it differently. For example, n by itself is simply a letter, but when you precede it with a backslash, it becomes \n, which is the newline character.
As you can probably guess, \ also needs to be escaped so it doesn't function like an escape character. You have to... escape the escape, essentially.
See the Python 3 documentation for string literals.
A hacky way of printing a backslash that doesn't involve escaping is to pass its character code to chr:
>>> print(chr(92))
\
print(fr"\{''}")
or how about this
print(r"\ "[0])
For completeness: A backslash can also be escaped as a hex sequence: "\x5c"; or a short Unicode sequence: "\u005c"; or a long Unicode sequence: "\U0000005c". All of these will produce a string with a single backslash, which Python will happily report back to you in its canonical representation - '\\'.
s='\'(-inf-24.5]\'' #this in not working
what should be put before \ to include it?
we have to assign s '\'(-inf-24.5]\''
the last two characters are two single quotes and not a single double quote.
the string should literally contain the given single backslashes as the string is to be inserted as it is in a column.
You can try this:
>>> s="\\'(-inf-24.5]\\'"
>>> print s
\'(-inf-24.5]\'
or
>>> s="'\\'(-inf-24.5]\\''"
>>> print s
'\'(-inf-24.5]\''
Basically, you will need to escape the backslash, when you write \' normally, python treats it as the ' being escaped. Also, python strings can be either "", or '', so you can mix them togather to get the desired result.
>>> s = r"'\'(-inf-24.5]\''"
>>> s
"'\\'(-inf-24.5]\\''"
>>> print(s)
'\'(-inf-24.5]\''
Prepending r before a string denotes a raw string, basically indicating to the interpreter that that string's characters should be taken literally. The only thing it can't do is end a string with a backslash (such a backslash would have to be concatenated from a separate string).
This question already has answers here:
python: replace a double \\ in a path with a single \
(3 answers)
Closed 8 years ago.
I Have a string having path of folder like below
>>> path
'\\\\sdgte\\ssdfdaa\\asfdsf'
I want to replace \\ with \ . I tried to replace but does not work as below
>>> path.replace('\\','\')
File "<input>", line 1
path.replace('\\','\')
^
SyntaxError: EOL while scanning string literal
Any Help will be highly appreciated.
There is no "\\" in the string. If you print it instead of looking at its representation you'll see the value that the string actually contains.
>>> print path
\\sdgte\ssdfdaa\asfdsf
You should use the escape charachter '\' to escape each \ in your string
path.replace('\\\\','\\')
you probably don't need to replace anything. \ is a special character in python that means "the next character, literally" in string literals. That is, if you want a string, containg a backslash, you'd probably type "\\":
>>> len('\\')
1
>>> print '\\'
\
>>> print '\\\\foo\\bar'
\\foo\bar
>>>
The reason you're getting that SyntaxError is the same reason you're seeing the doubled backslashes to begin with: backslash is the "escape" character, used to indicate the start of a special sequence, like "\n" for line feed, which would otherwise be difficult to represent in a string. The backslash character itself therefore has to be represented by a double backslash.
On the other hand, if you don't need to use any escape sequences within a string, you can preface the string with "r" instead of doubling the backslashes:
path.replace(r'\\', r'\')
path.replace(r'\\', '\\')
"r" indicates a "raw" string.
The problem you are running into, is that \ is an escape character. Instead of reading that as
replace '\\' with '\'
python is reading your argument as "replace the single backslash character with the single quotation mark character". The reason you are getting the error you are, is because python is ignoring your second single quotation mark because it thinks that is what you want it to do.
What you want is:
path.replace('\\\\', '\\')
you have to escape all backslashes because they are special.
Just a simple question concerning raw string, regex pattern and replacement:
I have a string variable defined as follow:
> print repr(foo)
'\n\t\t\n\t\tIf (GUTIAttach>=1) //In case of GUTI attach Enodeb should not ask RRCUecapa again\n\t\tUECapInfo;//Mps("( \\"rat_Type\\":0 \\"ueCapabilitiesRAT_Container\\":hex:011c0000000080 )");
My problem are characters "(" and ")", I want to replace them by "\(" and "\)" inside the raw string because it will be used after as a regular expression pattern.
I tried to use this method:
foo_tmp= [inc.replace(')', '\)') for inc in foo]
foo_tmp= [inc.replace('(', '\)') for inc in foo_tmp]
foo = "".join(foo_tmp)
the result gives:
> print repr(foo)
'\n\t\t\n\t\tIf \\(GUTIAttach>=1\\) //In case of GUTI attach Enodeb should not ask RRCUecapa again\n\t\t{\n\t\t\tUECapInfo;//Mps\\("\\( \\"rat_Type\\":0 \\"ueCapabilitiesRAT_Container\\":hex:011c0000000080 \\)"\\);
Characters "(" and ")" have been replaced by "\\(" and "//)" instead of "\(" and "\)".
That's a bit unexpected for me, so do you know how I can proceed to get just a single slash without changing the other part of the string?
Note: The method .decode('string_escape') is also not working due to the rest of string. Double slashes already present in the original raw string must not change.
Thanks a lot for your help
Use the re.escape() function to escape regular expression meta characters for you.
What you are seeing is otherwise perfectly normal Python behaviour; you are looking at a python literal representation; the output can be pasted back into a Python interpreter and recreate the value. As such, anything that could be interpreted as an escape code is escaped for you; a single \ would normally be doubled to prevent it being interpreted as the start of an escape sequence:
>>> '\('
'\\('
>>> print '\\('
\(
You can see this at work in other places in your foo string; the \n character combination represents a newline character, not two separate characters \ and n. If you wanted to include a literal \ and n in the text, you'd have to double the backslash to \\n. Further on into the value of foo you'll find \\", which is a single backslash followed by a " quote.
This question already has answers here:
How can I print a single backslash?
(4 answers)
Closed 7 months ago.
I am trying replace a backslash '\' in a string with the following code
string = "<P style='TEXT-INDENT'>\B7 </P>"
result = string.replace("\",'')
result:
------------------------------------------------------------
File "<ipython console>", line 1
result = string.replace("\",'')
^
SyntaxError: EOL while scanning string literal
Here i don't need the back slashes because actually i am parsing an xml file which has a tag in the above format, so if backslashes are there it is displaying invalid token during parsing
Can i know how to replace the backslashes with empty string in python
We need to specify that we want to replace a string that contains a single backslash. We cannot write that as "\", because the backslash is escaping the intended closing double-quote. We also cannot use a raw string literal for this: r"\" does not work.
Instead, we simply escape the backslash using another backslash:
result = string.replace("\\","")
The error is because you did not add a escape character to your '\', you should give \\ for backslash (\)
In [147]: foo = "a\c\d" # example string with backslashes
In [148]: foo
Out[148]: 'a\\c\\d'
In [149]: foo.replace('\\', " ")
Out[149]: 'a c d'
In [150]: foo.replace('\\', "")
Out[150]: 'acd'
In Python, as explained in the documentation:
The backslash () character is used to escape characters that otherwise have a special meaning, such as newline, backslash itself, or the quote character.
So, in order to replace \ in a string, you need to escape the backslash itself with another backslash, thus:
>>> "this is a \ I want to replace".replace("\\", "?")
'this is a ? I want to replace'
Using regular expressions:
import re
new_string = re.sub("\\\\", "", old_string)
The trick here is that "\\\\" is a string literal describing a string containing two backslashes (each one is escaped), then the regex engine compiles that into a pattern that will match one backslash (doing a separate layer of unescaping).
Adding a solution if string='abcd\nop.png'
result = string.replace("\\","")
This above won't work as it'll give result='abcd\nop.png'.
Here if you see \n is a newline character. So we have to replace backslah char in raw string(as there '\n' won't be detected)
string.encode('unicode_escape')
result = string.replace("\\", "")
#result=abcdnop.png
You need to escape '\' with one extra backslash to compare actually with \.. So you should use '\'..
See Python Documentation - section 2.4 for all the escape sequences in Python.. And how you should handle them..
It's August 2020.
Python 3.8.1
Pandas 1.1.0
At this point in time I used both the double \ backslash AND the r.
df.replace([r'\\'], [''], regex=True, inplace=True)
Cheers.