How the loop should iterate. I'm a beginner trying to create a Python program to print a word backwards based on old knowledge from a few years ago. It does a few other things but they are just printed statements are don't pose a problem. Here is my code:

count = 0
while count < 100:
    word_var = input("Enter ONE word with NO spaces:")
    def split(word_var):
        return list(word_var)
    word_array = split(word_var)
    m = 0
    i = len(word_array)-1-m
    print("The number of letters in your word is:", i)
    while m < len(word_array):
        if m < i:
            word_array[m], word_array[i - m] = word_array[i - m], word_array[m]
            m = m   1
        else:
            break
    m = m   1

    print(''.join(word_array))
    count = count   1
    print("You've typed:",count,"word(s).")

Here is the problem section:

        if m < i:
            word_array[m], word_array[i - m] = word_array[i - m], word_array[m]
            m = m   1
        else:
            break
     m = m   1 

My main problem is that it seems like the second while loop is not iterating when the word is more than five letters long. For example, if I input the word "should" into the program I get back out dhouls. It seems as if only one interchange of letters is being performed. I figure this is a problem with the if statement in that nested while loop but I can't seem to find what is wrong with it. I carefully sketched out how I think the if statement works in the photo attached.

CodePudding user response：

Your if condition is wrong. You want to compare the two indices that you will use in the list, but the second one is not i, but i-m. So change it to:

if m < i - m:

This corrects your issue. It should be noted that in Python you can reverse string just like this:

print(word_var[::-1])

CodePudding user response：

There are two issues:

1. The counting of the letters isn't correct. You should just output the length of word_array.

2. You're iterating the while loop too many times. You should terminate it when m equals or exceeds len(word_array) // 2. Otherwise, you'll unreverse the letters and get the original word back.

i = len(word_array)-1
print("The number of letters in your word is:", len(word_array))
while m < len(word_array) // 2:
    word_array[m], word_array[i - m] = word_array[i - m], word_array[m]
    m = m   1

This outputs:

Enter ONE word with NO spaces:should
The number of letters in your word is: 6
dluohs
You've typed: 1 word(s).

CodePudding user response：

I like your project and appreciate your efforts. This a another way to reverse a string using a list variable and the insert() method. word_array = []

word_var = input('Your word : ')
word_array = []

for c in word_var:
    word_array.insert(0, c)

word_reversed = ''.join(word_array)
print(word_var, '->', word_reversed)

output :

should -> dluohs