Question

我想知道如何通过索引导航finditer正则表达式操作生成的对象。

我的字符串是s = "fish oil X22 stack peanut C4"

这是我的代码：

import re
words = re.finditer('\S+', s)
has_digits = re.compile(r'\d').search
for word in words:
    if has_digits(word.group()):
        print (the word that is two words back)

期望输出=

fish
stack

Answer 1

您可以使用deque来保存元素。然后这变得容易：

import re
from collections import deque
s = 'fish oil X22 stack peanut C4'
words = re.finditer('\S+', s)
has_digits = re.compile(r'\d').search
deq = deque([],2)
for word in words:
    wordtxt = word.group()
    if has_digits(wordtxt):
        print (deq[0])
    deq.append(wordtxt)

有点不清楚字符串会发生什么：

s = 'fish oil X22 stack C4'

它应该打印＆＃34; fish＆＃34;和＆＃34;石油＆＃34;或者＆＃34; fish＆＃34;和＆＃34; X22＆＃34;。另外，如果第一个子串是＆＃34; X22＆＃34 ;?在我的回答中，这将导致IndexError，但很难知道你想用它做什么...

Answer 2

您可以使用itertools.tee和itertools.izip：

import re
import itertools as it

s = "fish oil X22 stack peanut C4"
words = re.finditer('\S+', s)
has_digits = re.compile(r'\d').search
words, words_copy = it.tee(words)
next(words); next(words)       #Skip the first two words of one iterator
for word, back_word in it.izip(words, words_copy):
    if has_digits(word.group()):
            print(back_word.group())

通过索引与re.finditer循环匹配

2 个答案: