我想用 Python 中的字母替换单词

Question

Code:

list = ['hello','world']
list2 = ['a','b']
string = 'hello'# should output a 
string_fin = ''
for s in string:
    for i, j in zip (list, list2):
        if s == i:
            string_fin += j
print(string_fin)

I want to write hello or world in string = '' and to get the output a or b

I get which is nothing

The reason this is happening is because hello and world have more characters than a and b when I try something that has the same amount of characters as a or b it works

Please help

Thanks

Answer 1

Better to store your lists as a dictionary, so you can do an easy lookup:

mapping = {'hello':'a', 'world':'b'}
string = 'hello or world'
out = []
for s in string.split():
    out.append( mapping.get( s, s ) )
print(' '.join(out))

Purists will note that the for loop can be made into a one-liner:

mapping = {'hello':'a', 'world':'b'}
string = 'hello or world'
out = ' '.join(mapping.get(s,s) for s in string.split())
print(out)

Answer 2

Your program's main loop never runs because string is empty: So your program is basically:

list = ['hello','world']
list2 = ['a','b']
string = ''
string_fin = ''
print(string_fin)

Although based on how you worded your question, it is really hard to understand what you are trying to accomplish, but here is my go.

• You have two lists: list1 and list2 ( Please do not name your list list as it is a reserved keyword, use list1 instead! )
• You want to check whether each word in your string matches with any word in your first list.
• If it matches you want to take the corresponding word or letter from your second list, and append it into the string string_fin .
• Finally, when you looped through all the words in the list, you print the content of string_fin .

The correct way to do this would be to split your string variable, and get each word stored in it.

string = 'hello or world'
stringWords = string.split()

Now, stringWords contains ['hello', 'or', 'world'] . But I think you are not interested in the item or . So you can remove this item from the list, by using remove() .

if 'or' in stringWords:
    stringWords.remove('or')

Now you have the words that you are interested in. And we want to check whether any word in the first list matches with these words. (Remember, I renamed the first list from list to list1 to prevent any unexpected behavior.)

for word in stringWords:
    tempIndex = list1.index(word)
    temp = list2[tempIndex]
    string_fin += temp

However, using index raises ValueError if a match is not found, so depending on your program logic, you may need to catch an exception and handle it. The string string_fin will now contain ab or a or b depending on the value inside string .

Now, since you wanted to print something like a or b , you can instead create a list and store the matching words in it, and then, join this list using or separator.

string_fin = (' or ').join(tempList)

A complete program now will look like this:

list1 = ['hello', 'world']
list2 = ['a', 'b']
string = 'hello or world'
tempList = []
stringWords = string.split()

if 'or' in stringWords:
    stringWords.remove('or')

for word in stringWords:
    tempIndex = list1.index(word)
    temp = list2[tempIndex]
    tempList.append(temp)

string_fin = ' or '.join(tempList)
print(string_fin)