我有一个 DataFrame 看起来像这样
ColA | ColB | ColC | ColD |
-----|------|------|------|
100 | A | X1 | NaN |
200 | B | X2 | AAA |
300 | C | X3 | NaN |
我想根据 ColA 的值填充 ColD 的缺失值。我需要的结果是这样的:
if value in ColA = 100 then value in ColD = "BBB"
if value in ColA = 300 then value in ColD = "CCC"
ColA | ColB | ColC | ColD |
-----|------|------|------|
100 | A | X1 | BBB |
200 | B | X2 | AAA |
300 | C | X3 | CCC |
最佳答案
您可以使用 combine_first
或 fillna
:
df.ColD = df.ColD.combine_first(df.ColA)
print (df)
ColA ColB ColC ColD
0 100 A X1 100
1 200 B X2 AAA
2 300 C X3 300
或者:
df.ColD = df.ColD.fillna(df.ColA)
print (df)
ColA ColB ColC ColD
0 100 A X1 100
1 200 B X2 AAA
2 300 C X3 300
编辑:首先使用 map
对于 Series
s
,然后通过此 Series
combine_first
或 fillna
:
d = {100: "BBB", 300:'CCC'}
s = df.ColA.map(d)
print (s)
0 BBB
1 NaN
2 CCC
Name: ColA, dtype: object
df.ColD = df.ColD.combine_first(s)
print (df)
ColA ColB ColC ColD
0 100 A X1 BBB
1 200 B X2 AAA
2 300 C X3 CCC
它只替换NaN
:
print (df)
ColA ColB ColC ColD
0 100 A X1 EEE <- changed value to EEE
1 200 B X2 AAA
2 300 C X3 NaN
d = {100: "BBB", 300:'CCC'}
s = df.ColA.map(d)
df.ColD = df.ColD.combine_first(s)
print (df)
ColA ColB ColC ColD
0 100 A X1 EEE
1 200 B X2 AAA
2 300 C X3 CCC
关于python - 根据同一行中另一列的值填充缺失值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42471164/