python – 计算多个子字符串一次出现在字符串中的次数

2023年5月7日 270次阅读

我在
Python中创建一个简单的脚本,用于评估分数系统上密码的强度,该分数系统根据是否包含学校的大写或小写字母,数字和符号来给出和获取分数.

其中一个要求是它检查英国QWERTY键盘上从左到右连续的3个字母或数字,并为每个实例取出5个点.例如,密码’qwer123’将因’qwe’,’wer’和’123’而失去15分.怎么可以实现呢？我目前的代码如下.

def check():
  user_password_score=0
  password_capitals=False
  password_lowers=False
  password_numbers=False
  password_symbols=False
  password_explanation_check=False
  ascii_codes=[]
  password_explanation=[]
  print("The only characters allowed in the passwords are upper and lower case letters, numbers and these symbols; !, $, %, ^, &, *, (, ), _, -, = and +.\n")
  user_password=str(input("Enter the password you would like to get checked: "))
  print("")
  if len(user_password)>24 or len(user_password)<8:
    print("That password is not between 8 and 24 characters and so the Password Checker can't evaluate it.")
    menu()
  for i in user_password:
    ascii_code=ord(i)
    #print(ascii_code)
    ascii_codes.append(ascii_code)
  #print(ascii_codes)
  for i in range(len(ascii_codes)):
    if ascii_codes[i]>64 and ascii_codes[i]<90:
      password_capitals=True
    elif ascii_codes[i]>96 and ascii_codes[i]<123:
      password_lowers=True
    elif ascii_codes[i]>47 and ascii_codes[i]<58:
      password_numbers=True
    elif ascii_codes[i] in (33,36,37,94,38,42,40,41,45,95,61,43):
      password_symbols=True
    else:
      print("Your password contains characters that aren't allowed.\n")
      menu()
  if password_capitals==True:
    user_password_score+=5
  if password_lowers==True:
    user_password_score+=5
  if password_numbers==True:
    user_password_score+=5
  if password_symbols==True:
    user_password_score+=5
  if password_capitals==True and password_lowers==True and password_numbers==True and password_symbols==True:
    user_password_score+=10
  if password_numbers==False and password_symbols==False:
    user_password_score-=5
  if password_capitals==False and password_lowers==False and password_symbols==False:
    user_password_score-=5
  if password_capitals==False and password_lowers==False and password_numbers==False:
    user_password_score-=5
  #print(user_password_score)
  if user_password_score>20:
    print("Your password is strong.\n")
  else:
    print("That password is weak.\n")
  #don't forget you still need to add the thing that checks for 'qwe' and other stuff.
  menu()

最佳答案 您可以在一组字符串中存储禁用的序列,并在每次有人使用该序列时减少分数.

password = "qwert123"
score = 42          # initial score
sequences = {       # all in lowercase because of the `lower()` in the loop
    "qwertyuiopasdfghjklzxcvbnm",
    "azertyuiopqsdfghjklmwxcvbn",
    "abcdefghijklmnopqrstuvwxyz",
    "01234567890"
}
match_length = 3                        # length threshold for the sanction
sequences.update({s[::-1] for s in sequences})      # do we allow reverse ?

for c in range(len(password)-match_length+1):
    for seq in sequences:
        if password[c:c+match_length].lower() in seq:
            score-=5
            print(f"'{password[c:c+match_length]}' => -5 !")
            break   # Don't flag the same letters more than once

print(score) # 22 (42-4*5)
点赞