dln385 dln385 - 7 months ago 42
Python Question

Process escape sequences in a string in Python

Sometimes when I get input from a file or the user, I get a string with escape sequences in it. I would like to process the escape sequences in the same way that Python processes escape sequences in string literals.

For example, let's say

myString
is defined as:

>>> myString = "spam\\neggs"
>>> print(myString)
spam\neggs


I want a function (I'll call it
process
) that does this:

>>> print(process(myString))
spam
eggs


It's important that the function can process all of the escape sequences in Python (listed in a table in the link above).

Does Python have a function to do this?

Answer

The correct thing to do is use the 'string-escape' code to decode the string.

>>> myString = "spam\\neggs"
>>> decoded_string = bytes(myString, "utf-8").decode("unicode_escape") # python3 
>>> decoded_string = myString.decode('string_escape') # python2
>>> print(decoded_string)
spam
eggs

Don't use the AST or eval. Using the string codecs is much safer.