Python 定位字符串

# -*- coding: utf-8 -*-

__author__ = 'Evilxr'

import string

_string =("Vm0wd2QyUXlVWGxWV30d4WFlURn164dVRlpzWkc5V"
"1JteDBaVVYwV0ZKdGVGWlZiVFZyVmxVeFY3yTkljRmhoTVhCU"
"VZtcEdZV015U2tWVWJHaG9UVlZ3VlZadGNFZFRNbEpJVm10V1"
"VtSk3lRazlVVkVKTFUFAceB00BxWmtWMXBFVWxwV01ERTBWMn"
"RvUjFWdF55NsWlhiR2hYWVd0d2RscFdXbUZrUjA1R1drWndWM"
"DFFUlRGV1ZFb3dWakZhV0ZOcmFHaFNlbXhXVm0weGIxSkdXbG"
"RYYlVaclVqRmFTRll5TVRSVk1rcElaSHBDVjAxdVVuWldha3B"
"IWXpGT2RWVnNXbWxoTUhCWl4A4YxWlNSMlF52UmtkWGEyUllZ"
"bGhT5V0ZSV1pGTk5SbFowWlVaT1ZXSkdjREZWVjNoelZqRmFO"
"bEZZYUZaaGExcG9WakJhVDJOdFJrZFhiV3hUVFcxb2IxWnRjR"
"U5pTVVWNFdrVmtXRmRIVWxsWmJHaFRZMVpTVjJGRlRsTmlSbk"
"JaV2xWYVQxWlhTa2RqUm1oYVRVWktXRll3V21GU2JFNTBZVVp"
"44rYUdFeGNHOVdha0poVXpGa1dGSnJaR2hTTW1oUFZGY3hiMW"
"RzV1hoWGJFNVRUVlp3TUZadGRHdFdNa3B6VTIxR1ZWWjZWblp"
"XUkVaVFZteGtjbHBIY0U1V2EzQlhWbFprTkZNeFRYaFhhMXBQ"
"VmxacmJFMHdVU1V6UkElM0QlM0Q")
mark = 0
while mark < len(_string) - 8:
# 构造字符串
result = _string[mark: mark + 8]
try:
# 长度为8
assert len(result) == 8
except:
print u'字符串长度不为8'
break
try:
# 它的前两位是大写英文
assert result[0] in string.ascii_uppercase
assert result[1] in string.ascii_uppercase
# 它的3、4位是小写英文
assert result[2] in string.ascii_lowercase
assert result[3] in string.ascii_lowercase
# 它的第5位和第8位是同一个字符
assert result[4] == result[7]
# 它的第6、7位是数字
assert result[5] in string.digits
assert result[6] in string.digits

print 'success', result
break
except:
mark = mark +1

success FAceB00B