[英]Convert multiple columns into dict after groupby in pandas
我有一個 dataframe
df = pd.DataFrame({"a":[1,1,1,2,2,2,3,3], "b":["a","a","a","b","b","b","c","c"], "c":[0,0,1,0,1,1,0,1], "d":["x","y","z","x","y","y","z","x"]})
a b c d
0 1 a 0 x
1 1 a 0 y
2 1 a 1 z
3 2 b 0 x
4 2 b 1 y
5 2 b 1 y
6 3 c 0 z
7 3 c 1 x
我想在 a 列和 b 列上進行分組以獲取以下 output:
a b e
0 1 a [{'c': 0, 'd': 'x'}, {'c': 0, 'd': 'y'}, {'c': 1, 'd': 'z'}]
1 2 b [{'c': 0, 'd': 'x'}, {'c': 1, 'd': 'y'}, {'c': 1, 'd': 'y'}]
2 3 c [{'c': 0, 'd': 'z'}, {'c': 1, 'd': 'x'}]
我的解決方案:
new_df = df.groupby(["a","b"])["c","d"].apply(lambda x: x.to_dict(orient="records")).reset_index(name="e")
但問題是它的行為不一致,有時我會遇到以下錯誤:
reset_index() 得到了一個意外的關鍵字參數“名稱”
如果有人指出上述解決方案中的問題或提供替代方法,那將很有幫助。
你可以做
new=ddf.groupby(['a','b'])[['c','d']].apply(lambda x : x.to_dict('r')).to_frame('e').reset_index()
Out[13]:
a b e
0 1 a [{'c': 0, 'd': 'x'}, {'c': 0, 'd': 'y'}, {'c':...
1 2 b [{'c': 0, 'd': 'x'}, {'c': 1, 'd': 'y'}, {'c':...
2 3 c [{'c': 0, 'd': 'z'}, {'c': 1, 'd': 'x'}]
或者,我們可以這樣做:
df['e'] = df[['c', 'd']].agg(lambda s: dict(zip(s.index, s.values)), axis=1)
df1 = df.groupby(['a', 'b'])['e'].agg(list).reset_index()
# print(df1)
a b e
0 1 a [{'c': 0, 'd': 'x'}, {'c': 0, 'd': 'y'}, {'c':...
1 2 b [{'c': 0, 'd': 'x'}, {'c': 1, 'd': 'y'}, {'c':...
2 3 c [{'c': 0, 'd': 'z'}, {'c': 1, 'd': 'x'}]
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