Question

我的目标是编写一个比较两个字符串的程序，并显示前两个不匹配字符之间的差异。

示例：

str1 = 'dog'
str2 = 'doc'

应该返回'gc'

我知道我尝试使用的代码很糟糕，但我希望收到一些提示。这是我努力解决这个让我无处可停的练习：

# firstly I had tried to split the strings into separate letters
str1 = input("Enter first string:").split()
str2 = input("Enter second string:").split()

# then creating a new variable to store the result after  comparing the strings
result = ''

# after that trying to compare the strings using a for loop
for letter in str1:
    for letter in str2:
        if letter(str1) != letter(str2):
            result = result + letter
            print (result)

Answer 1

def first_difference(str1, str2):
    for a, b in zip(str1, str2):
        if a != b:
            return a+b

用法：

>>> first_difference('dog','doc')
'gc'

但正如@ZdaR在评论中指出的那样，如果一个字符串是另一个字符串的前缀且长度不同，则结果未定义（在本例中为None）。

Answer 2

我通过使用单个循环更改了解决方案。

这个怎么样：

# First, I removed the split... it is already an array
str1 = input("Enter first string:")
str2 = input("Enter second string:")

#then creating a new variable to store the result after  
#comparing the strings. You note that I added result2 because 
#if string 2 is longer than string 1 then you have extra characters 
#in result 2, if string 1 is  longer then the result you want to take 
#a look at is result 2

result1 = ''
result2 = ''

#handle the case where one string is longer than the other
maxlen=len(str2) if len(str1)<len(str2) else len(str1)

#loop through the characters
for i in range(maxlen):
  #use a slice rather than index in case one string longer than other
  letter1=str1[i:i+1]
  letter2=str2[i:i+1]
  #create string with differences
  if letter1 != letter2:
    result1+=letter1
    result2+=letter2

#print out result
print ("Letters different in string 1:",result1)
print ("Letters different in string 2:",result2)

比较两个字符串并返回差异。 Python 3

2 个答案: