Deprecate suffixes in merge producing duplicate columns #40991
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phofl
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Deprecate
mroeschke
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Apr 20, 2021
jreback
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Apr 20, 2021
| left = DataFrame({"a": [1, 2, 3], "b": 1, "b_x": 2}) | ||
| right = DataFrame({"a": [1, 2, 3], "b": 2}) | ||
| with tm.assert_produces_warning(FutureWarning): | ||
| merge(left, right, on="a") |
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can you assert the results here
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Done and added another test
| left = DataFrame([[1, 1, 1], [2, 2, 2]], columns=["a", "b", "b"]) | ||
| right = DataFrame({"a": [1, 3], "b": 2}) | ||
| result = merge(left, right, on="a") | ||
| expected = DataFrame([[1, 1, 1, 2]], columns=["a", "b_x", "b_x", "b_y"]) |
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is this the expected result?
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Yes, I wanted to avoid raising when we already get duplicate columns as input, because the collisions in this case are not caused by the suffixes
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kk, can you add a comment to this effect
mroeschke
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Apr 20, 2021
jreback
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Apr 20, 2021
|
thanks @phofl |
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I think we should not allow these column collisions at all. Hence deprecating and raising in 2.0
Alternative here would be to add an
errorskeyword to the merge and join functions as @simonjayhawkins mentioned in the op.