Explode rows pandas dataframe

Question

I have a pandas dataframe like the below:

Letters	Date
'Letters : a'	2021
'Letters : a,b,c'	2019
'Letters : a,b'	2017

I want to be turned into the below, using pandas/python.

Letters	Date
a	2021
a	2019
b	2019
c	2019
a	2017
b	2017

Thank you in advance

Your rows are really formatted like this `'Letters : a,b,c'`? (with quotes) — Corralien, Dec 28 '21 at 14:43
No need to worry about the quotes i've entered them just to show that it is a string. — Dim Tsi, Dec 28 '21 at 14:49

score 2 · Accepted Answer · answered Dec 28 '21 at 14:52

We can use Series.str.split to parse out the relevant information in to a list prior to using explode.

df.assign(
    Letters=df.Letters \
              .str \
              .split(" : ", expand=True)[1] \
              .str.split(",") \
         ) \
  .explode("Letters")

  Letters  Date
0       a  2021
1       a  2019
1       b  2019
1       c  2019
2       a  2017
2       b  2017

Please note the index is not reset in this answer, you can do that if you need by calling reset_index.

score 1 · Answer 2 · answered Dec 28 '21 at 14:54

1

Use explode after split your values:

>>> df.assign(Letters=df['Letters'].str.split(',')).explode('Letters')

  Letters  Date
0       a  2021
1       a  2019
1       b  2019
1       c  2019
2       a  2017
2       b  2017

answered Dec 28 '21 at 14:54

Corralien

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https://stackoverflow.com/questions/12680754/split-explode-pandas-dataframe-string-entry-to-separate-rows – jezrael Dec 28 '21 at 14:55
Why again dupe? – jezrael Dec 28 '21 at 14:55
It is many times answered, so why not closed? – jezrael Dec 28 '21 at 14:56
Apologies ,just wanted an extra mile with the split(" : ", expand=True)[1] step that @gold_cy provided. – Dim Tsi Dec 28 '21 at 16:41

Explode rows pandas dataframe

2 Answers2