How to do ‘lateral view explode()’ in pandas [duplicate]

by

Method 1 (OP)

pd.DataFrame([[item]+list(df.loc[line,'B':]) for line in df.index for item in df.loc[line,'A']],
             columns=df.columns)

Method 2 (pir)

df1 = df.A.apply(pd.Series).stack().rename('A')
df2 = df1.to_frame().reset_index(1, drop=True)
df2.join(df.B).reset_index(drop=True)

Method 3 (pir)

A = np.asarray(df.A.values.tolist())
B = np.stack([df.B for _ in xrange(A.shape[1])]).T
P = np.stack([A, B])
pd.Panel(P, items=['A', 'B']).to_frame().reset_index(drop=True)

Thanks @user113531 for the reference to Alexander’s answer. I had to modify it to work.

Method 4 (@Alexander) LINKED ANSWER

(Follow link and Up Vote if this was helpful)

rows = []
for i, row in df.iterrows():
    for a in row.A:
        rows.append([a, row.B])

pd.DataFrame(rows, columns=df.columns)

Timings

Method 4 (Alexander’s) is the best followed by Method 3

enter image description here

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