用str.translate删除反斜杠

Question

I wrote the following Python2.7 code to remove digits and the backslash character (\\) from some string. I attempted to use the str.translate method, because I had learned that it is very efficient. The code below successfully removed digits from the string x, but is unable to remove the single backslash in y. What did I do wrong?

import string    
x = 'xb7'
y = '\xb7'
print x.translate(None, '\\' + string.digits)
print y.translate(None, '\\' + string.digits)

Answer 1

You don't have any strings with backslashes. x has the characters 'x' , 'b' , and '7' , while y has a single character, '·' , denoted by the hex code b7 . If you want the literal string '\\xb7' , with four characters in it, use a raw string by prefixing an r in front of the literal.

>>> import string
>>> print r'\xb7'.translate(None, '\\' + string.digits)
xb

Answer 2

Your algorithm works much better when there's actually a backslash to remove. Tigerhawk already showed you your hexadecimal string. Here's another simplistic example to help, showing the unchanged original y .

import string
x = 'xb7'
y = '\\xb7'
print x, y
kill = '\\' + string.digits
print "kill", kill
print x.translate(None, kill)
print y.translate(None, kill)
print "y=", y

Output:

xb7 \xb7
kill \0123456789
xb
xb
y= \xb7