Python中的2D数组索引

Question

I want to calculate how many times each word of an array is there in text file. I am getting the output if write the print statement in shell. But not when I run it as a file . I am getting this error "IndexError: list index out of range". I am a beginner in python please help me out.

from collections import Counter
from array import *
import string
cnt=Counter()
file = open('output.txt', 'r')
word =[ ]
c=[ ]
count =0
first_word =[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
word_count = [ ]
new_array =['CC','CD','DT','EX','FW','IN','JJ','JJR','JJS','LS','MD','NN','NNS','NNP','NNPS','PDT',
                       'POS','PRP','PRP$','RB','RBR','RBS','RP','SYM','TO','UH','VB','VBD','VBZ','WDT','WP$','WP','WRB']
for line in file:
      words = line.split()
      word.append(words)
for i in range(0,30):
      for j in range(0,33):
            if(new_array[j] in word[i][0]):
                  first_word[j]+=1
            else:
                  continue
print first_word

Answer 1

Don't use explicit values for range when you wan't to iterate over lists , rather use length of lists you are iterating. This way there will be no index errors . So, replace:

for i in range(0,30):
      for j in range(0,33):

with:

for i in range(len(word)):
      for j in range(len(first_word)):

I guess it will fix the issue. Also when you have to initialize a list with similar values like:

first_word =[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]

there is a simple way in python for this as:

>>> first_word = [0]*33
>>> first_word 
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Answer 2

I think the following code should get you the results you need:

wordsFromFile = []    
f = open("output.txt", 'r')
for each_line in f:
    wordsFromFile.extend(each_line.strip().split(" "))
f.close()

print wordsFromFile

new_array = ['CC','CD','DT','EX','FW','IN','JJ','JJR','JJS','LS','MD','NN','NNS','NNP','NNPS','PDT',
                       'POS','PRP','PRP$','RB','RBR','RBS','RP','SYM','TO','UH','VB','VBD','VBZ','WDT','WP$','WP','WRB']
first_word = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]

for eachWordFromFile in wordsFromFile:
    if eachWordFromFile in new_array: 
        first_word[new_array.index(eachWordFromFile)] += 1

#output results: 
for i in range(0,33):
    print str(new_array[i]) + ": " + str(first_word[i])