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[英]Merge Pandas 2 DataFrame, with different number of rows and columns
[英]Merge rows inside dataframe by replacing nans in different columns
我有一个df:
df = pd.DataFrame([[1, np.nan, "filled", 3], [1, "filled", np.nan, 3], [1, "filled", np.nan, 4]], columns = ["a", "b", "c", "d"])
a b c d
0 1 NaN filled 3
1 1 filled NaN 3
2 1 filled NaN 4
我的最终结果应该是:
df = pd.DataFrame([[1, "filled", "filled", 3], [1, "filled", np.nan, 4]], columns = ["a", "b", "c", "d"])
a b c d
0 1 filled filled 3
1 1 filled NaN 4
所以我想合并除了列b和c以外的所有方面相同的行。 问题是除了列b和c之外,并不总是会有另一行相同。
想不出怎么用df.groupby(["a", "d"]).apply()
得到我想要的东西。
您可以检查groupby
+ first
,它会选择先不要NaN
值作为输出
df.groupby(['a','d'],as_index=False).first()
Out[897]:
a d b c
0 1 3 filled filled
1 1 4 filled NaN
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