[英]replacing one column with another column but not missing value
I have a dataframe我有一个数据框
name g1 g2
a 1 1
a 0 na
a 1 3
b 1 na
b 2 na
b 3 4
c 4 na
I want to move g2 values to g1 without moving the na the returned columns should be我想将 g2 值移动到 g1 而不移动 na 返回的列应该是
name g1 g2
a 1 1
a 0 na
a 3 3
b 1 na
b 2 na
b 4 4
c 4 na
I used df.replace(g1, g2),
but that will move the NA as well.我使用了
df.replace(g1, g2),
但这也会移动 NA。 Is there anyone to not move the NA有没有人不移动NA
This is one approach:这是一种方法:
data = [['a', '1', '1'], ['a', '0', np.nan], ['a', '1', '3'], ['b', '1', np.nan],
['b', '2', np.nan], ['b', '3', '4'], ['c', '4', np.nan]]
df = pd.DataFrame(data, columns=['name', 'g1', 'g2'])
df['g1'] = df['g2'].fillna(df['g1'])
print(df)
Output:输出:
name g1 g2
0 a 1 1
1 a 0 NaN
2 a 3 3
3 b 1 NaN
4 b 2 NaN
5 b 4 4
6 c 4 NaN
您可以使用notna
检查:
df.loc[df['g2'].notna(), 'g1'] = df['g2']
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