Question

该程序将加密消息。它将带有偶数编号索引的所有值并将其放入列表中，并将赔率保留在第一个列表中。最后它会给你一个转换后加密信息。示例：ababab成为aaabbb

以上是程序应该做的事情，但是当我实际运行程序时，会给出完全相同的字符串而不是加密版本。

crypt = [] # list to store original answers
original = raw_input("Enter your string: ") # prompts user for their desired string
crypt.append(original) # stores user answers in list crypt
crypt2 = [] # all the items with an even index from list crypt
x = 0

for a in crypt:
   if x % 2 == 1: # checks for oddness in the index value
      crypt2.append(a) # adds value associated with index to list crypt2
      crypt.remove(a) # removes value associated with index from list crypt
   x += 1

print crypt + crypt2

我的程序的逻辑部分有问题吗？

Answer 1

尝试使用print语句来查看循环的行为，您会发现crypt实际上只包含一个条目。

执行crypt.append(original)时，它会将整个输入作为加密列表中的单个条目。然后，当你执行for a in crypt时，只有一次成为整个用户输入，然后循环终止。

如果您想循环使用字符，请使用 crypt.extend 而不是crypt.append。

Answer 2

new = ''.join([char for i, char in enumerate(original) if i % 2 == 0])

这也可能有用。

Answer 3

当你进行循环时：

for a in crypt

你遍历crypt列表中只有1个元素的对象，它是用户编写的字符串。将程序更改为：

original = raw_input("Enter your string: ") # prompts user for their desired
crypt = [] # list to store original answers
crypt2 = [] # all the items with an even index from list crypt
x = 0
print original
for a in original:
    if x % 2 == 1: # checks for oddness in the index 
        crypt2.append(a) # adds value associated with index to list crypt2
    else:
        crypt.append(a)
    x += 1
print crypt + crypt2

Answer 4

在crypt.append(original)之后，crypt为['ababab']而不是['a', 'b', 'a', 'b', 'a', 'a']。此外，除非你知道自己在做什么，否则在迭代它时最好不要改变列表。为了您的目的，迭代original就足够了。

crypt = []
original = raw_input("Enter your string: ") 
crypt = [c for c in original] # convert str to list
crypt2 = [] 
x = 0

for a in original:
   if x % 2 == 1: # checks for oddness in the index value
      crypt2.append(a) # adds value associated with index to list crypt2
      crypt.remove(a) # removes value associated with index from list crypt
   x += 1

print crypt + crypt2

输出：

['a', 'a', 'a', 'b', 'b', 'b'] 
# if you want 'aaabbb', using print ''.join(crypt + crypt2)
# this will give you 'aaabbb'

一种简单的方法：

>>> original = 'ababab'
>>> original[::2] + original[1::2]
'aaabbb'
>>>

加密返回与输入原始字符串相同的字符串

4 个答案: