Python Pandas Merge Key Error

Question

Why does the following fail with KeyError 'NUM'?

result = pandas.merge(sdf_subset, dfgeom, how='inner', on=['ID', 'NUM'])

The column 'ID' exists in sdf_subset and 'NUM' exists in dfgeom. I have checked the datatype and both are Int64.

Any ideas?

check if the column names have spaces, what does sdf_subset.columns.tolist() and dfgeom.columns.tolist() show? — EdChum
– EdChum, Commented May 23, 2017 at 11:17

Allen Qin · Accepted Answer · 2017-05-23 11:20:13Z

5

# you need to use left_on and right_on if the joining key is different between the dataframes.
result = pandas.merge(sdf_subset, dfgeom, how='inner', left_on='ID', right_on='NUM')

answered May 23, 2017 at 11:20

Allen Qin

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Allen Qin Over a year ago

You are welcome. Please accept the answer if it helps.

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