从python中的.txt文件中提取电子邮件地址

Question

I would like to parse out e-mail addresses from several text files in Python. In a first attempt, I tried to get the following element that includes an e-mail address from a list of strings ( '2To whom correspondence should be addressed. E-mail: joachim+pnas@uci.edu.\\n' ).

When I try to find the list element that includes the e-mail address via i.find("@") == 0 it does not give me the content[i] . Am I misunderstanding the .find() function? Is there a better way to do this?

from os import listdir

TextFileList = []
PathInput = "C:/Users/p282705/Desktop/PythonProjects/ExtractingEmailList/text/"

# Count the number of different files you have!
for filename in listdir(PathInput):
    if filename.endswith(".txt"):  # In case you accidentally put other files in directory
        TextFileList.append(filename)

for i in TextFileList:
    file = open(PathInput + i, 'r')
    content = file.readlines()
    file.close()

for i in content:
    if i.find("@") == 0:
        print(i)

Answer 1

The standard way of checking whether a string contains a character, in Python, is using the in operator . In your case, that would be:

for i in content:
    if "@" in i:
        print(i)

The find method, as you where using, returns the position where the @ character is located , starting at 0, as described in the Python official documentation .

For instance, in the string abc@google.com , it will return 3. In case the character is not located, it will return -1. The equivalent code would be:

for i in content:
    if i.find("@") != -1:
        print(i)

However, this is considered unpythonic and the in operator usage is preferred.

Answer 2

'Find' function in python returns the index number of that character in a string. Maybe you can try this?

list = i.split(' ') # To split the string in words
for x in list:    # search each word in list for @ character
    if x.find("@") != -1:
        print(x)

Answer 3

Find returns the index if you find the substring you are searching for. This isn't correct for what you are trying to do.

You would be better using a Regular Expression or RE to search for an occurence of @. In your case, you may come into as situation where there are more than one email address per line (Again I don't know your input data so I can't take a guess)

Something along these lines would benefit you:

import re
for i in content:
    findEmail = re.search(r'[\w\.-]+@[\w\.-]+', i)
    if findEmail:
     print(findEmail.group(0))

You would need to adjust this for valid email addresses... I'm not entirely sure if you can have symbols like +...