Python:错误:类型错误:findall() 缺少 1 个必需的位置参数:“字符串" [英] Python: Error:TypeError: findall() missing 1 required positional argument: 'string'

问题描述

我正在尝试使用特定参数清理文本文档.尝试了 x=... 行的不同迭代，但程序无法读取所有行.

I am trying to scrub a text document with specific parameters. Have tried different iterations of the x=... line but the program isn't able to read the all line.

import re
#import csv

text = open(r'C:\Users\Vincent\Documents\python\theSortingHat\100000DirtyNames.txt') #open text file
for line in text: #iterate through every line
    #return list of names in that line
    x = re.findall ('^([a-zA-Z]-?$')
    #if an actual name is found
    if x != 0:
        print(x)

我收到:

错误:类型错误:findall() 缺少 1 个必需的位置参数:'字符串'

Error:TypeError: findall() missing 1 required positional argument: 'string'

推荐答案

您需要查找字符串中的某些内容.问题是你只给了 re.findall 一个参数，你还应该给 line 作为参数.您的正则表达式也有问题，并且您没有关闭您的组(即 ())，这是什么使它成为无效的正则表达式.

You need to find something in a string. The problem is that you gave re.findall only the one parameter, you should also give line as a parameter. You also had some problem with your regex and you didn't close your group (i.e. ()), what made it to a not valid regex.

这就是你想要的答案:

import re

text = open(r'C:\Users\Vincent\Documents\python\theSortingHat\100000DirtyNames.txt') #open text file
for line in text: #iterate through every line
    #return list of names in that line
    x = re.findall('^([a-zA-Z])-?$', line)
    #if an actual name is found
    if x != 0:
        print(x)

<小时>

关于正则表达式，听起来像这样帖子可能会有所帮助
TL;博士:
你可以使用这个正则表达式:

---

About the regex, sounds like this post might help
TL;DR:
you can use this regex maybe:

^[A-Z]'?[- a-zA-Z]+$

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