Pandas: merged data frame has more rows than the original ones

Question

I have a dataset df with this shape (1038828, 6)

lib_source = df['LIB_SOURCE']
lib_source = pd.get_dummies(lib_source, prefix='source', prefix_sep='_')

lib_source has the same shape : (1038828, 2)

After I merge lib_source with df :

df = df.join(lib_source)

And now df shape is (1777590, 7).

Why please I don'k keep the initial shape please? Thanks.

This means you have duplicated indices. Can you provide a reproducible sample? — mozway, Mar 14 '22 at 15:54
Ok. No I have not reproducible sample. So a reindex of df should fix? — Theo75, Mar 14 '22 at 15:57

score 0 · Answer 1 · answered Mar 14 '22 at 15:57

0

Try using pd.concat instead:

df = pd.concat([df, lib_source], axis=1)

answered Mar 14 '22 at 15:57

1 Answers1