Python For Loop僅循環一次（對於文本文件中的每一行）

Question

我目前處於軟件開發學位的第三年，我正在考慮在明年推出一些安全模塊，我選擇了「Violent Python「作爲介紹並學習一種新語言，但是我被困在第一個練習中。

我不是新手，編程，也許我只是累了 - 它已經在小睡一整天 - 但這種簡單的腳本不會工作：

import crypt 
def testPass(cryptPass): 
salt = cryptPass[0:2] 
dictFile = open('dictionary.txt') 
for word in dictFile.readlines(): 
    word = word.strip('\n') 
    print "[*] Attempting password: "+word+"\n" 
    cryptWord = crypt.crypt(word,salt) 
    if (cryptWord == cryptPass): 
    print "[+] Found Password: "+word+"\n" 
    return 
    print "[-] Password Not Found.\n" 
    return 
def main(): 
passFile = open('passwords.txt') 
for line in passFile.readlines(): 
    if ":" in line: 
    user = line.split(':')[0] 
    cryptPass = line.split(':')[1].strip(' ') 
    print "[*] Cracking Password For: "+user 
    testPass(cryptPass) 
if __name__ == "__main__": 
main() 

password.txt的有來自/兩個用戶etc/passwd（受害者和根），並通過它們循環良好。我在我的dictionary.txt三個密碼，並由於某種原因，只嘗試第一個密碼：

[*] Cracking Password For: victim 
[*] Attempting password: break 

[-] Password Not Found. 

[*] Cracking Password For: root 
[*] Attempting password: break 

[-] Password Not Found. 

有人可以解釋爲什麼上面從書中擡起的代碼沒有工作？我設法通過使用「with open」來解決問題：

with open('dictionary.txt') as f: 
for word in f: 
    word = word.strip("\n") 
    cryptWord = crypt.crypt(word,salt) 
    if (cryptWord == cryptPass): 
    print "[+] Found Password: "+word+"\n" 
    return 
    print "[-] Password Not Found.\n" 
    return 

Answer 1

這是一個縮進錯誤。對於事情的正常工作，你的「testPass」功能應該是這樣的：

def testPass(cryptPass): 
    salt = cryptPass[0:2] 
    dictFile = open('dictionary.txt') 
    for word in dictFile.readlines(): 
     word = word.strip('\n') 
     print "[*] Attempting password: "+word+"\n" 
     cryptWord = crypt.crypt(word,salt) 
     if (cryptWord == cryptPass): 
      print "[+] Found Password: "+word+"\n" 
      return 
    print "[-] Password Not Found.\n" 
    return 

這樣的話，它會遍歷字典中的每一個字，並返回一旦發現密碼。如果它循環遍歷所有內容而沒有找到它，則應該，然後打印「未找到密碼」。你的問題是你的代碼（爲了清晰而間隔一點）實際上是這樣縮進的：

def testPass(cryptPass): 
    salt = cryptPass[0:2] 
    dictFile = open('dictionary.txt') 
    for word in dictFile.readlines(): 
     word = word.strip('\n') 
     print "[*] Attempting password: "+word+"\n" 
     cryptWord = crypt.crypt(word,salt) 
     if (cryptWord == cryptPass): 
      print "[+] Found Password: "+word+"\n" 
      return 
     print "[-] Password Not Found.\n" 
     return 

看到區別？像這樣，它只會檢查第一個單詞，因爲第二個「return」在循環中。請驗證您的縮進（理想情況下4個空格，@jonrsharpe說，或一個標籤）並再次嘗試。我懷疑這會解決你的問題。