[英]Python “IndexError: string index out of range” (Beginner)
因此,对于编程作业,我们必须在python中重新编写sort函数以对单词列表进行排序。 到目前为止,我已经使它能够根据每个字母的第一个字母对单词进行排序,现在我尝试运行递归以在第一个字母或任何字母相同的情况下仍对它进行排序。 我在“ IndexError:字符串索引超出范围”错误时遇到问题。 我到目前为止所拥有的是
def insertion_sort(bookwords):
for index in range(1,len(bookwords)):
global word
word=bookwords[index]
i=index-1
word_checker(bookwords, 0, i)
def word_checker(bookwords, num, i):
while i>=0:
wordleft=bookwords[i]
if ord(word[num])<ord(wordleft[num]):
bookwords[i+1]=bookwords[i]
bookwords[i]=word
i=i-1
elif ord(word[num])==ord(wordleft[num]):
num=num+1
word_checker(bookwords, num, i)
else:
break
bookwords=["michael", "maddy", "michelle", "monstor", "money", "mountain", "miniscus", "mega"]
insertion_sort(bookwords)
print bookwords
我猜num正在变得比单词大,但是当字母不相同时,它会运行很多次而不会停止,所以我有点困惑为什么这样做。 任何帮助将不胜感激
UPDATE
好的,现在可以工作了,但是当我将其放入提供的代码中以测试大约700000个单词的速度时,它运行了30多个,直到我将其停止为止,因为排序功能花了5秒钟。 这也是我的一部分代码
import re
import pygame
# 159.172 assignment 2
#
def mysort(words):
for index in range(1,len(words)):
word=words[index]
i=index-1
word_checker(words, i, word)
def word_checker(words, i, word):
while i>=0:
wordleft=words[i]
if word==wordleft:
break
elif word<wordleft:
words[i+1]=words[i]
words[i]=word
i=i-1
else:
return
# Do NOT change anything below here:
#
# Compare two lists
def compare(l1,l2):
if len(l1) != len(l2):
return False
for a,b in zip(l1,l2):
if a!=b:
return False
return True
# Open the book
book=open("allsherlock.txt", "rt")
# Make a list of all the words in the book
bookwords=[]
for line in book:
for word in re.findall(r'\w+', line):
bookwords.append(word.lower())
print "Loaded",len(bookwords),"words"
sortedbookwords=bookwords[:]
pygame.init()
# Use the sort function to sort the words for testing
sortedbookwords.sort()
starttime=pygame.time.get_ticks()
# Call our sort function
mysort(bookwords)
print "Sort took",pygame.time.get_ticks()-starttime,"ms"
print "Correct sort:",compare(bookwords,sortedbookwords)
您必须更改此:
elif ord(word[num])==ord(wordleft[num]):
num=num+1
word_checker(bookwords, num, i)
else:
至:
elif ord(word[num])==ord(wordleft[num]):
num=num+1
else:
然后会打印: ['maddy', 'mega', 'money', 'michael', 'michelle', 'miniscus', 'monstor', 'mountain']
我仍然看不到在那儿进行递归的意义,我认为插入排序不会做递归。
按字符比较时,算法已损坏,但是python可以为您比较字符串,因此这将给出正确的结果:
def insertion_sort(bookwords):
for index in range(1,len(bookwords)):
global word
word=bookwords[index]
i=index-1
word_checker(bookwords, i)
def word_checker(bookwords, i):
while i>=0:
wordleft=bookwords[i]
if word<wordleft:
bookwords[i+1]=bookwords[i]
bookwords[i]=word
i=i-1
bookwords=["michael", "maddy", "michelle", "monstor", "money", "mountain", "miniscus", "mega"]
insertion_sort(bookwords)
print bookwords #prints ['maddy', 'mega', 'michael', 'michelle', 'miniscus', 'money', 'monstor', 'mountain']
几件事:
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