Pandas 和 scikit-learn：KeyError：[....] 不在索引中
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Pandas and scikit-learn: KeyError: [....] not in index
提问by ScalaBoy
I do not understand why do I get the error KeyError: '[ 1351 1352 1353 ... 13500 13501 13502] not in index'when I run this code:
我不明白为什么KeyError: '[ 1351 1352 1353 ... 13500 13501 13502] not in index'运行此代码时会出现错误：
cv = KFold(n_splits=10)
for train_index, test_index in cv.split(X):
f_train_X, f_valid_X = X[train_index], X[test_index]
f_train_y, f_valid_y = y[train_index], y[test_index]
I use X(a Pandas dataframe) to split I cv.split(X).
我使用X（一个 Pandas 数据框）来分割 I cv.split(X)。
X.shape
y.shape
Out: (13503, 17)
Out: (13503,)
回答by seralouk
The problem is the way you are trying to index the Xusing X[train_index].You need to use .locor .ilocsince you have pandasdataframe.
问题在于您尝试索引Xusing 的方式X[train_index]。您需要使用.loc或.iloc因为您有pandas数据框。
Use this
用这个
cv = KFold(n_splits=10)
for train_index, test_index in cv.split(X):
f_train_X, f_valid_X = X.iloc[train_index], X.iloc[test_index]
f_train_y, f_valid_y = y.iloc[train_index], y.iloc[test_index]
1st way: Example using iloc
第一种方式：使用示例 iloc
import pandas as pd
import numpy as np
df = pd.DataFrame(np.random.randint(0,100,size=(100, 4)), columns=list('ABCD'))
df[[1,2]]
#KeyError: '[1 2] not in index'
df.iloc[[1,2]]
# A B C D
#1 25 97 78 74
#2 6 84 16 21
2nd way: Example by converting pandas to numpy in advance
第二种方式：例如提前将pandas转换为numpy
df = df.values
#now this should work fine
df[[1,2]]
#array([[25, 97, 78, 74],
# [ 6, 84, 16, 21]])
