尝试通过切断多索引并设置列’Z’条件值来设置col’X’值.我可以很容易地设置col’X’值,但是我在试图找出条件时遇到困难.
import pandas as pd
FOOBAR = (['foo','foo','foo','foo','bar','bar','bar','bar'])
NUM1 = ([5,5,6,6,8,8,5,5])
NUM2 = ([1,1,2,2,3,3,1,1])
NUM3 = ([1001,1002,1002,1002,1003,1004,1004,1005])
#build and name index using data
index = pd.MultiIndex.from_arrays([FOOBAR,NUM1,NUM2,NUM3],
names=['iFOOBAR','iNUM1','iNUM2','iNUM3'])
df = pd.DataFrame({'X': [ 0, 1, 2, 3, 4, 5, 6, 7],
'Y': [ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'],
'Z': [ 1, 2, 2, 4, 5, 6, 7, 7],
'FL': [0.1,0.1,0.2,0.2,0.4,0.4,0.1,0.1]
}, index=index)
df.sortlevel(inplace=True)
idx = pd.IndexSlice
#original df
# FL X Y Z
#iFOOBAR iNUM1 iNUM2 iNUM3
#bar 5 1 1004 0.1 6 G 7
# 1005 0.1 7 H 7
# 8 3 1003 0.4 4 E 5
# 1004 0.4 5 F 6
#foo 5 1 1001 0.1 0 A 1
# 1002 0.1 1 B 2
# 6 2 1002 0.2 2 C 2
# 1002 0.2 3 D 4
#set value in 'X' based on index
newdf = df.loc[idx['foo',5,1,:], idx['X']] = 999
#new df
# FL X Y Z
#iFOOBAR iNUM1 iNUM2 iNUM3
#bar 5 1 1004 0.1 6 G 7
# 1005 0.1 7 H 7
# 8 3 1003 0.4 4 E 5
# 1004 0.4 5 F 6
#foo 5 1 1001 0.1 999 A 1
# 1002 0.1 999 B 2
# 6 2 1002 0.2 2 C 2
# 1002 0.2 3 D 4
#set value in 'X' base on index and 'Z' == 2 ???
#nextdf = df.loc[idx['foo',5,1,:], idx['Z'== 2]], 'X' = 999
#next df: desired output
# FL X Y Z
#iFOOBAR iNUM1 iNUM2 iNUM3
#bar 5 1 1004 0.1 6 G 7
# 1005 0.1 7 H 7
# 8 3 1003 0.4 4 E 5
# 1004 0.4 5 F 6
#foo 5 1 1001 0.1 0 A 1
# 1002 0.1 999 B 2
# 6 2 1002 0.2 2 C 2
# 1002 0.2 3 D 4
解决方法:
试试这个:(一行)
df.loc[idx[:,5,1,(df['Z'] == 2)],idx['X']] = 999
df
FL X Y Z
iFOOBAR iNUM1 iNUM2 iNUM3
bar 5 1 1004 0.1 6 G 7
1005 0.1 7 H 7
8 3 1003 0.4 4 E 5
1004 0.4 5 F 6
foo 5 1 1001 0.1 0 A 1
1002 0.1 999 B 2
6 2 1002 0.2 2 C 2
1002 0.2 3 D 4
In [126]:
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