178

I have a column in my dataframe like this:

range
"(2,30)"
"(50,290)"
"(400,1000)"
...

and I want to replace the , comma with - dash. I'm currently using this method but nothing is changed.

org_info_exc['range'].replace(',', '-', inplace=True)

Can anybody help?

smci
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UserYmY
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7 Answers7

362

Use the vectorised str method replace:

df['range'] = df['range'].str.replace(',','-')

df
      range
0    (2-30)
1  (50-290)

EDIT: so if we look at what you tried and why it didn't work:

df['range'].replace(',','-',inplace=True)

from the docs we see this description:

str or regex: str: string exactly matching to_replace will be replaced with value

So because the str values do not match, no replacement occurs, compare with the following:

df = pd.DataFrame({'range':['(2,30)',',']})
df['range'].replace(',','-', inplace=True)

df['range']

0    (2,30)
1         -
Name: range, dtype: object

here we get an exact match on the second row and the replacement occurs.

smci
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EdChum
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89

For anyone else arriving here from Google search on how to do a string replacement on all columns (for example, if one has multiple columns like the OP's 'range' column): Pandas has a built in replace method available on a dataframe object.

df.replace(',', '-', regex=True)

Source: Docs

kevcisme
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9

Replace all commas with underscore in the column names 

data.columns= data.columns.str.replace(' ','_',regex=True)
adiga
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Rameez Ahmad
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9

If you only need to replace characters in one specific column, somehow regex=True and in place=True all failed, I think this way will work:

data["column_name"] = data["column_name"].apply(lambda x: x.replace("characters_need_to_replace", "new_characters"))

lambda is more like a function that works like a for loop in this scenario. x here represents every one of the entries in the current column.

The only thing you need to do is to change the "column_name", "characters_need_to_replace" and "new_characters".

Nancy K
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  • This worked for my requirement. Thank you. – FMFF Dec 10 '20 at 00:57
  • This is what I ended up doing to replace, but I get the "A value is trying to be set on a copy of a slice from a DataFrame." warning. The resulting dataframe is exactly what I want, but the warning is off-putting. Rather than just turning the warning off, I'm in search of a non-warning-inducing way. – Chris Feb 09 '21 at 19:05
  • Thanks! Also you need to do some conversion in parameter of lambda function, like all x to string using `str(x)` – charles Oct 19 '21 at 00:27
7

In addition, for those looking to replace more than one character in a column, you can do it using regular expressions:

import re
chars_to_remove = ['.', '-', '(', ')', '']
regular_expression = '[' + re.escape (''. join (chars_to_remove)) + ']'

df['string_col'].str.replace(regular_expression, '', regex=True)
cdutra
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0

If you want to remove two or more elements from a string, example the characters '$' and ',' :

Column_Name
===========
$100,000
$1,100,000

... then use:

data.Column_Name.str.replace("[$,]", "", regex=True)

=> [ 100000, 1100000 ]

smci
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Leandro Marotti
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0

Almost similar to the answer by Nancy K, this works for me:

data["column_name"] = data["column_name"].apply(lambda x: x.str.replace("characters_need_to_replace", "new_characters"))
Freddie
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