当我在程序中输入单词时，如何使程序接受任何情况

Question

I am writing a program where a starting sentence is displayed and the user has to input a word that is in the sentence, so that the program can tell the user the position the word is in the sentence. I want the program to accept every case but at the moment it only accepts UPPER case. Can someone please help me on how to make it case insensitive and still tell the user the positions of the words when they input them? Thanks :)

Here is my code so far:

import time

sentence = ("ASK NOT WHAT YOUR COUNTRY CAN DO FOR YOU ASK WHAT YOU CAN DO FOR YOUR COUNTRY")

sentence2 = sentence.split()

print(sentence)

time.sleep(1)

word = input("Enter Word: ")

print(word)

sentence == sentence.lower()

word == word.lower()

if word in sentence:

    print("Word is valid")

elif word not in sentence:

    print("Word is invalid")


for (num, x) in enumerate(sentence2):

    if word == x:

       print ("Your word is in position ",num+1,"!")

Answer 1

The == operator checks for equivalency, it doesn't assign anything. This line of code: sentence == sentence.lower() should be sentence = sentence.lower() and the line under that should be word = word.lower() .

In addition, since you split sentence into sentence2 at the very beginning of the program, sentence.lower() does not change sentence2 , meaning it will never get the position of the word because sentence2 is all uppercase and word is all lowercase. To fix this, get rid of sentence2 and replace your last for statement with something like this

for (num, x) in enumerate(sentence.split()):

Answer 2

Convert word to uppercase with word = word.lower() and remove the following lines:

sentence == sentence.lower()
word == word.lower()

Answer 3

This is the most straightforward way I can think of

>>> import collections
>>> position_index = collections.defaultdict(list)
>>> sentence = "ASK NOT WHAT YOUR COUNTRY CAN DO FOR YOU ASK WHAT YOU CAN DO FOR YOUR COUNTRY"
>>> for index, word in enumerate(sentence.split()):
...     position_index[word].append(index)
...
>>> position_index["can".upper()]
[5, 12]
>>> position_index["what".upper()]
[2, 10]

The for loop builds a dictionary-like data structure that looks like this

{'DO': [6, 13], 'WHAT': [2, 10], 'FOR': [7, 14], 'COUNTRY': [4, 16], 'ASK': [0, 9], 'CAN': [5, 12], 'NOT': [1], 'YOU': [8, 11], 'YOUR': [3, 15]}

Now that you have a dictionary you need to handle words that are not present as well. Because this uses a defaultdict you get the added benefit that direct lookups on missing indexes will return an empty list.

>>> print(position_index["they".upper()])
[]

So you can simply

>>> word = "what"
>>> positions = position_index[word.upper()]
>>> if positions:
...     print("The word '%s' appears at position(s): %s" %(word, ",".join(map(str, positions)),))
... else:
...     print("The word '%s' does not appear" %(word,))
...
The word 'what' appears at position(s): 2, 10

Answer 4

def findPos(sentence, word):
sentence = sentence.lower().split(' ')
word = word.lower()
index = 0
for i in sentence:
    if word == i:
        print '%s is a valid word and is found at position %s'%(word, index)
        return
    index += 1
    print i
print '%s is not a valid word'%word

sentence = 'Ask not what you can do... I forgot!!'
word = raw_input('What is your word?: ')
findPos(sentence, word)

Currently this will not work for things that end in punctuation (forgot, do). This is because we directly evaluate the two. The only way I see around that is to do the in operator. This of course will give way to even larger issues, (Input:a Output:Ask, what, can. This is because 'a' is technically in all three!)! Hope this helps! This also only returns the first index of the word. This could be modified by having a list of positions. At the end of the loop if len(list) > 0 we return , bypassing the second print. It's up to you!