的.txt
文件保持数据如下(源:在2章here “datingTestSet2.txt”):在python2.7.11中,为什么我不能删除fileopen代码?
40920 8.326976 0.953952 largeDoses
14488 7.153469 1.673904 smallDoses
26052 1.441871 0.805124 didntLike
75136 13.147394 0.428964 didntLike
38344 1.669788 0.134296 didntLike
...
代码:
from numpy import *
import operator
from os import listdir
def file2matrix(filename):
fr = open(filename)
# arr = fr.readlines() # Code1!!!!!!!!!!!!!!!!!!!
numberOfLines = len(fr.readlines()) #get the number of lines in the file
returnMat = zeros((numberOfLines,3)) #prepare matrix to return
classLabelVector = [] #prepare labels return
fr = open(filename) # Code2!!!!!!!!!!!!!!!!!!!!!
index = 0
for line in fr.readlines():
line = line.strip()
listFromLine = line.split('\t')
returnMat[index,:] = listFromLine[0:3]
classLabelVector.append(int(listFromLine[-1]))
index += 1
return returnMat,classLabelVector
datingDataMat, datingLabels = file2matrix('datingTestSet2.txt')
此函数的结果是:
datingDataMat datingLabels
40920 8.326976 0.953952 3
14488 7.153469 1.673904 2
26052 1.441871 0.805124 1
75136 13.147394 0.428964 1
38344 1.669788 0.134296 1
72993 10.141740 1.032955 1
35948 6.830792 1.213192 3
42666 13.276369 0.543880 3
67497 8.631577 0.749278 1
35483 12.273169 1.508053 3
50242 3.723498 0.831917 1
... ... ... ...
我的问题是:
当我刚刚删除Code2(
fr = open(filename)
,其中index = 0
以上), 函数的结果变成全零矩阵,并且全零矢量。 为什么我不能删除Code2?不第一行(fr = open(filename)
工作?当我刚刚加入代码1(
arr = fr.readlines()
),这是错误的。为什么???returnMat[index,:] = listFromLine[0:3] IndexError: index 0 is out of bounds for axis 0 with size 0