各种正则表达式案例

1. 查找空行：^[ \t]*$\r\n

2. 查找最后一位是小写字母的8位十六进制数：0x[0-9]{7,7}[a-z]{1,1}

3. 查找至少有一位是小写字母的8位十六进制数：0x(?=[0-9]{0,7}[a-z])[a-z0-9]{8,8}

4. 截取当前行第一个括号前面的全部字符：(?=^[^(|^（^\r|^\n]*[(|（])^[^(|^（]*

import re#查找至少有一位是小写字母的8位十六进制数，并将其修改为大写def hex_to_upper(hexStr):    listHex = re.findall("0x(?=[0-9]{0,7}[a-z])[a-z0-9]{8,8}", hexStr)    print listHex    newStr = re.sub(r"0x(?=[0-9]{0,7}[a-z])[a-z0-9]{8,8}", "0XLLLLLLLL", hexStr)    for obj in listHex:        print obj, '-----------', obj[2:]        newStr = re.sub(r"0XLLLLLLLL", '0x'+obj[2:].upper(), newStr, 1)    return newStrif __name__ == '__main__':    a = "oei0x7822CDE2lwnfnsodf0x7822abe2lsdksdf1023900x98de293c988e9we0x98112931ii"    print a    print hex_to_upper(a)