CODEWITHSUNDEEP
pythonstringconcatenationeol
Alex TheWebGroup
Alex TheWebGroup

Reputation: 175

EOL while concatenating string + path

I need to concatenate specific folder path with a string, for example:

mystring = "blablabla"
path = "C:\folder\whatever\"

printing (path + mystring) should return: C:\folder\whatever\blablabla

However I always get the EOL error, and it's a must the path to have the slash like this: \ and not like this: /

Please show me the way, I tried with r' it's not working, I tried adding double "", nothing works and I can't figure it out.

Upvotes: 1

Views: 440

Answers (3)

user5728855
user5728855

Reputation: 86

Two things.

First, with regards to the EOL error, my best guess - without access to the actual python session - is that python was complaining because you have an unterminated string caused by the final " character being escaped, which will happend even if the string is prefixed with r. My opinion is that you should drop the prefix and just correctly espace all backslashes like so: \\.

In your example, paththen becomes path = "C:\\folder\\whatever\\"

Secondly, instead of manually concatenating paths, you should use os.path.join:

import os
mystring = "blablabla"
path = "C:\\folder\\whatever"
print os.path.join(path, mystring)

## prints C:\\folder\\whatever\\blablabla

Note that os.path will use the path convetions for the operating system where the application is running, so the above code will produce erroneous/unexpected results if you run it on, say, Linux. Check the notes on the top of the page that I have linked for details.

Upvotes: 1

dfrib
dfrib

Reputation: 73186

Either use escape character \\ for \:

mystring = "blablabla"
path = "C:\\folder\\whatever\\"

conc = path + mystring
print(conc)
# C:\folder\whatever\blablabla

Or, make use of raw strings, however moving the last backslash from end of path to the start of myString:

mystring = r"\blablabla"
path = r"C:\folder\whatever"

conc = path + mystring
print(conc)
# C:\folder\whatever\blablabla

The reason why your own raw string approach didn't work is that a raw strings may not end with a single backslash:

Specifically, a raw literal cannot end in a single backslash (since the backslash would escape the following quote character).

From

Upvotes: 1

Mike Müller
Mike Müller

Reputation: 85482

Always use os.path.join() to join paths and the r prefix to allow single back slashes as Windows path separators:

r"C:\folder\whatever"

Now, now trailing back slash is needed:

>>> import os
>>> mystring = "blablabla"
>>> path = r"C:\folder\whatever"
>>> os.path.join(path, mystring)
'C:\\folder\\whatever\\blablabla'

Upvotes: 2

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