List Manipulation in Python - Breakout and Transpose

Question

Despite the insane number of list questions on this website, I still haven't been able to get this right.

First element in the list is another list. Trying to break that out and then populate it vertically.

have = [[['v', 'e', 'r', 't'], 'A', 'B', 'C', 'D'],
        [['v', 'e', 'r', 't'], 'E', 'F', 'G', 'H']]

want = [['v', 'A', 'B', 'C', 'D'],
        ['e', 'A', 'B', 'C', 'D'],
        ['r', 'A', 'B', 'C', 'D'],
        ['t', 'A', 'B', 'C', 'D'],
        ['v', 'E', 'F', 'G', 'H'],
        ['e', 'E', 'F', 'G', 'H'],
        ['r', 'E', 'F', 'G', 'H'],
        ['t', 'E', 'F', 'G', 'H']]

score 1 · Answer 1 · answered Sep 18 '17 at 20:44

1

Use this:

have = [[['v', 'e', 'r', 't'], 'A', 'B', 'C', 'D'],
    [['v', 'e', 'r', 't'], 'E', 'F', 'G', 'H']]
df = pd.DataFrame(have)

(df[0].apply(pd.Series).stack().reset_index(level=1, drop=True)
     .to_frame()
     .merge(df, left_index=True, right_index=True,suffixes=('','_r'))
     .drop('0_r',axis=1).values.tolist())

Output:

[['v', 'A', 'B', 'C', 'D'],
 ['e', 'A', 'B', 'C', 'D'],
 ['r', 'A', 'B', 'C', 'D'],
 ['t', 'A', 'B', 'C', 'D'],
 ['v', 'E', 'F', 'G', 'H'],
 ['e', 'E', 'F', 'G', 'H'],
 ['r', 'E', 'F', 'G', 'H'],
 ['t', 'E', 'F', 'G', 'H']]

answered Sep 18 '17 at 20:44

Scott Boston

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Thanks Scott! Great answer and it worked for me. – Josh Sep 18 '17 at 21:48
I did, and marked it as answer. Not sure what happened with those phantom down votes. – Josh Sep 18 '17 at 22:21

List Manipulation in Python - Breakout and Transpose

1 Answers1