我有一个像这样的dafatframe:
A B
0 NaN string1
1 NaN string2
2 Nan string1
3 Nan string1
如何更改 A 列中的所有值,以便根据 B 列中同一索引处的条目是否包含某个字符串“stringX”来更改它们为 bool 值?
最佳答案
我认为您需要分配 bool 掩码,可以使用 eq
来代替 ==
或使用assign
:
#if need True False values by condition
stringX = "string1"
df['A'] = df['B'] == stringX
print (df)
A B
0 True string1
1 False string2
2 True string1
3 True string1
df['A'] = df['B'].eq(stringX)
print (df)
A B
0 True string1
1 False string2
2 True string1
3 True string1
df = df.assign(A=df['B'].eq(stringX))
print (df)
A B
0 True string1
1 False string2
2 True string1
3 True string1
#if need values of column by condition
df.loc[df['B'] == 'string1', 'A'] = df['B']
print (df)
A B
0 string1 string1
1 NaN string2
2 string1 string1
3 string1 string1
#if need scalar by condition
df.loc[df['B'] == 'string1', 'A'] = 1
print (df)
A B
0 1 string1
1 NaN string2
2 1 string1
3 1 string1
#if need if else condition with 2 scalars
df['A'] = np.where(df['B'] == 'string1', 1, 2)
print (df)
A B
0 1 string1
1 2 string2
2 1 string1
3 1 string1
关于python pandas - 根据另一列的内容将列中的值更改为 bool 值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45672516/