numpy - how can the string convert to int in python? -

numpy - how can the string convert to int in python? -

in machine learning in action chapter 2, 1 illustration reads records file, each line like:

124 110 223 largedoses

(forget actual meaning)

one function in knn.py is:

def file2matrix(filename): fr = open(filename) numberoflines = len(fr.readlines()) returnmat = zeros((numberoflines,3)) classlabelvector = [] fr = open(filename) index = 0 line in fr.readlines(): line = line.strip() listfromline = line.split('\t') returnmat[index,:] = listfromline[0:3] classlabelvector.append(int(listfromline[-1])) index += 1 homecoming returnmat,classlabelvector

the problem listfromline[-1] string ('largedoses', etc.), how can convert int?

in book, says numpy can handle this.

(from book : you have explicitly tell interpreter you’d integer version of lastly item in list, or give string version. usually, you’d have this, numpy takes care of details you.) however,

valueerror: invalid literal int() base of operations 10: 'largedoses'

occurs for

import knn knn.file2matrix('dataset.txt')

btw, book's chinese version different english language version.

string (indeed) cannot convert int, neither in python, nor in other environment,

however,

the solution is

put machine learning (indeed) in action

in case knn-input training / cross-validation records ( a.k.a. observations, examples )

do conform convention of [ 3x feature, 1x label]

use:

classlabelvector.append( listfromline[-1] ) # .append label, not int()

python numpy