正则表达式

import re

# ============= 笔记 =================
'''
re.match只匹配字符串的开始，如果字符串开始不符合正则表达式，则匹配失败，函数返回None；
而re.search匹配整个字符串，直到找到一个匹配。


# ==================================== #
'''
#  p:模式  s:要匹配的字符串


def match(p, s):
    matchobj = re.search(p, s)
    if matchobj:
        print('匹配成功')
        print("匹配的字符串是：", matchobj.group())
        #print("匹配的字符串的索引是：",matchobj.start(),matchObj.end())
    else:
        print("匹配失败")


def sub(in_file, out_file):
    with open(out_file, "w", encoding="utf-8") as f_write:
        for line in open(in_file):
            sub_line = re.sub('NV', 'GN', line)
            print(sub_line)
            f_write.write(sub_line)
        f_write.close()


pattern = 'abc'
string = 'hello abc dog'
match(pattern, string)

in_file = './in.txt'
out_file = './out.txt'
sub(in_file, out_file)