python readlines（）txt文件，无法由正则表达式识别

Question

在txt文件中，我想通过正则表达式识别一些url，然后将它们发送到新文件中。 但是不幸的是，我发现正则表达式无法识别readlines（）函数read的行。

# coding:utf-8

import re
import json

line1 = ''
text = ''
with open(r'all.log') as f:
    lines = f.readlines()
    for line in lines:
        line1 = line
        r = re.match('s',line) # pattern I use The most simple word ,just 's'
        if r:
            print(r.group())
        f.close()
        break

print(line1)
print(type(line1))
r = re.match('Hello',line1,re.DOTALL)

# but the same re.match method can be used with a 'content' str
content = 'Hello 1234567 is a number. Regex String' 
print(re.match('Hello',content).group())
if r:
    print(r.group())
else:
    print('you get nothing')`

也许我认为正则表达式在这种情况下不起作用？

结果： 你好1234567是一个数字。正则表达式字符串

你好 你什么也没得到 [以0.3秒完成]

print(line1) 
# line1 = Hello 1234567 is a number. Regex String
content = 'Hello 1234567 is a number. Regex String'

print(type(line1))
print(type(content))

r_line1 = re.match('Hello',line1)
r_content = re.match('Hello',content)

if r_line1:print(r_line1.group())
else:print('r_line1 get nothing')

if r_content:print(r_content.group())
else:print('r_content get nothing')

result：
Hello 1234567 is a number. Regex String

<type 'str'>
<type 'str'>
r_line1 get nothing
Hello
[Finished in 0.3s]