how can I remove point numbers: '(i)', '(ii)', '(iii)' in answers with regex from pandas dataframe?

user_15996907 0
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Suppose, I have a pandas dataframe consisting many rows for product name and columns describing their respective features. And they add some numbering system like 1., 2.,3.,... or a),b),c)....or (i),(ii),(iii),... etc. Now I want to remove them in data frame.

df.replace(regex=True, inplace=True, to_replace=r'["(i*)"|i*.|(a-zA-Z).|("("a-zA-z")")]', value=r'')

but the code is not working. It deletes all i's from the answers eg. consider becomes consder and I can remove a., b. etc if I give it individually i.e., to_replace=r'[a.|b.|A.|B.] but if the pattern is given, it's not working.

how can I remove '(i)', '(ii)', '(iii)' and '(a)', '(A)', 'a.', 'A.' ranges from A-Z and i for one or more with regex pandas dataframe?

Example

INPUT
(i) The cow has four legs. (ii) The cow eats grass. (iii) Cow gives us milk.

OR

a.The cow has four legs. b.The cow eats grass. c.Cow gives us milk.

OUTPUT
The cow has four legs. The cow eats grass. Cow gives us milk.

pandas python regex
2 Answers

Would you please try:

df.replace(regex=True, inplace=True, to_replace=r'^\(?(?:[ivxlcdm]+|[a-zA-Z]+|[0-9]+)[).]', value='')

Input:

(i) The cow has four legs.
(ii) The cow eats grass.
(iii) Cow gives us milk.
a.The cow has four legs.
b.The cow eats grass.
c.Cow gives us milk.
1.The cow has four legs.
2.The cow eats grass.
3.Cow gives us milk.
a)The cow has four legs.
b)The cow eats grass.
c)Cow gives us milk.

Output:

The cow eats grass.
Cow gives us milk.
The cow has four legs.
The cow eats grass.
Cow gives us milk.
The cow has four legs.
The cow eats grass.
Cow gives us milk.
The cow has four legs.
The cow eats grass.
Cow gives us milk.

Explanation of the regex ^\(?(?:[ivxlcdm]+|[a-zA-Z]+|[0-9]+)[).]:

  • ^ indicates the start of the string.
  • \(? matches a zero or one left parenthesis.
  • (?:[ivxlcdm]+|[a-zA-Z]+|[0-9]+) can be broken down either of:
    • [ivxlcdm]+ which matches Roman numerals.
    • [a-zA-Z]+ which matches alphabets.
    • [0-9]+ which matches digits.
  • [).] matches a right parenthesis or a dot.
user_85723800

If there can only be 1 or more times an i char (so no roman numerals) you might use:

\(?i+\)|\b(?:[A-Za-z]|\d+)\.

The pattern matches:

  • \(?i+\) Match an optional (, then 1+ times an i char and a )
  • | Or
  • \b A word boundary to prevent a partial match
  • (?: Non capture group
    • [A-Za-z] Match a single char A-Za-z
    • | Or
    • \d+ Match 1+ digits
  • ) Close non capture group
  • \. Match a dot

Regex demo

If you want to match roman numerals, you can see this post.

user_54249880
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