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Problem with exercise

The exercise asks me to replace each letter with it corresponding letter in the inverted alphabet (if there is an "a", need to replace it with a "z"). Here is my code. I am a bit newbie in Thai and this is the first "medium" exercise that I do. I receive an error in the line 5, anyone can help me? The code: str = input() alphabet = "abcdefghijklmnopqrstuvwxyz" re_alph = (alphabet[::-1]) for i in range(len(str)): str[i] = letter alphabet [letter] = place re_alph [place] = str[i] print (str)

14th Jan 2020, 8:45 PM
Tobias Fuentebuena Guardón
Tobias Fuentebuena Guardón - avatar
7 Antworten
+ 4
The problems appear to be in your for loop. When you say str[i] = letter, I think you mean to put letter = str[i], that means the variable letter is being assigned the value of the character at index i of str. (As a side note, it is not a good idea to use 'str' as a variable name as str() is used as a method to change a value to a string.) The same thing for the next line; alphabet[letter] = place, it should be the other way around, but here, letter is not an integer so you can't call the character at index 'letter' of the string alphabet, you need alphabet.index(letter) - this returns the index of 'alphabet' that 'letter' appears. I think your reversal habit is present in the next lone too. Lastly, you cannot amend individual characters of a string. str[i] = re_alph[place] is just not something you can do. I'd advise you to create a new empty string at the start (call it 'output' or something), and with each character you decode, add it to your output string and print that at the end.
14th Jan 2020, 9:03 PM
Russ
Russ - avatar
+ 2
letter hasn't been defined yet, and I believe the error is on line 6(str[i] = letter). I believe you mean: letter = str[i] There's another error in line 7, which I believe is typed backwards, again. You can correct those two errors, and see what else is wrong.
14th Jan 2020, 8:59 PM
Jianmin Chen
Jianmin Chen - avatar
+ 1
Easiest way is output += re_alph[place]
14th Jan 2020, 9:22 PM
Russ
Russ - avatar
0
Anda how can I do it? I am forgetting something because it only shows the last letter if I write this: Output = re_alph[place]
14th Jan 2020, 9:21 PM
Tobias Fuentebuena Guardón
Tobias Fuentebuena Guardón - avatar
0
Ok, i figured out (another way, more complicated so thank you) Now I have a problem, I guess, with the space character because I receive a "substring not found" in this code when I try to index the space. I added the space to the string in the "alphabet" variable but it doesn't recognize it words = input() alphabet = "abcdefghijklmnopqrstuvwxyz" re_alph = "zyxwvutsrqponmlkjihhfedcba" output = "" out = "" for i in range(len(words)): letter = words [i] place = int(alphabet.index(letter)) output = re_alph [place] out += output print (out)
14th Jan 2020, 9:31 PM
Tobias Fuentebuena Guardón
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0
Hello Alexander, the input is upper, lower and spaces I guess because Sololearn doesn't show me the last 3 tests if I am not Pro
14th Jan 2020, 9:56 PM
Tobias Fuentebuena Guardón
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As I said, the task is to take a string (with upper, lower and spaces at least) and replace every character with its counterpart in an inverted alphabet. I can do it with single words (receiven only lower output) but the code fails when I have a string with spaces in it, and I don't know how to ignore it because the expected output still has the spaces, I can't eliminate them
14th Jan 2020, 10:10 PM
Tobias Fuentebuena Guardón
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