Multiple symbols replace not working

Question

I need to check a string for some symbols and replace them with a whitespace. My code:

string = 'so\bad'

symbols = ['•', '!', '"', '#', '$', '%', '&', '\'', '(', ')', '*', '+', ',', '-', '.', '/', ':', ';', '<', '>', '=', '?', '@', '[', ']', '\\', '^', '_', '`', '{', '}', '~', '|', '"', '⌐', '¬', '«', '»', '£', '$', '°', '§', '–', '—']

for symbol in symbols:
    string = string.replace(symbol, ' ')

print string
>> sad

Why does it replace a\b with nothing?

Is the intended output: "so bad"? When running your code as is the output is : "so ad". — Copy and Paste, May 06 '16 at 18:38
I suspect it *is* printing the `o`, however `\b` is being interpreted as a single backspace character instead of "a backslash and then a b", so when it "prints", it backs up over the previous character. — John Gordon, May 06 '16 at 18:39
With that many symbols to replace, it might be easier to use `re.sub`. — TigerhawkT3, May 06 '16 at 18:48

score 3 · Answer 1 · edited May 23 '17 at 11:52

3

This is because \b is ASCII backspace character:

>>> string = 'so\bad'
>>> print string
sad

You can find it and all the other escape characters from Python Reference Manual.

In order to get the behavior you expect escape the backslash character or use raw strings:

# Both result to 'so bad'
string = 'so\\bad'
string = r'so\bad'

edited May 23 '17 at 11:52

Community

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answered May 06 '16 at 18:39

niemmi

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or r'so\bad', worth mentioning IMO – Amit Gold May 06 '16 at 18:53
@AmitGold: Thanks, modified answer accordingly – niemmi May 06 '16 at 18:59

Copy and Paste · Accepted Answer · 2016-05-06T18:47:32.853

1

The issue you are facing is the use of \ as a escape character.
\b is a special character (backspace)

Use a String literal with prefix r. With the r, backslashes \ are treated as literal

string = r'so\bad'

edited May 06 '16 at 18:47

answered May 06 '16 at 18:41

Copy and Paste

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score 0 · Answer 3 · answered May 06 '16 at 18:40

0

You are not replacing anything "\b" is backspace, moving your cursor to the left one step.

answered May 06 '16 at 18:40

tfv

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score 0 · Answer 4 · edited May 23 '17 at 11:59

0

Note that even if you omit the symbols list and your for symbol in symbols: code, you will always get the result "sad" when you print string. This is because \b means something as an ascii character, and is being interpreted together.

Check out this stackoverflow answer for a solution on how to work around this issue: How can I print out the string "\b" in Python

edited May 23 '17 at 11:59

Community

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answered May 06 '16 at 18:41

Projski

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Multiple symbols replace not working

4 Answers4