[Tutor] dont understand part of a code

[Alan Gauld]

On 02/07/16 11:46, Minhaj Ahmed via Tutor wrote:

> have underlined the part of code I do not understand and why it is there.

The mailing list is plain text so formatting like underline
doesn't show up. Fortunately you added a comment too...

> so_far = "-" * len(word)

so_far is whats printed as the result so far.

> used = []

used is the letters input so far

> while wrong < MAX_WRONG and so_far != word:
>     print(HANGMAN[wrong])
>     print("\nYou've used the following letterss:\n",used)
>     print("\nSo far,the word is:\n", so_far)
>     guess = input("\nEnter your guess: ")
>     guess = guess.upper()
> 
>     while guess in used:
>         print("You've already guessed the letter",guess)
...

>     if guess in word:
>         print("\nYes",guess,"is in the word!")
> 
>         new = ""
>         for i in range(len(word)):
>             if guess == word[i]:
>                 new += guess
>           *  else:*
> *                new += so_far[i]  # why is there a else code here?*

The else part is needed so that when the guess is noyt at the given
position the current value of so_far is put into new.

Lets assume the word is python
lets assume sop_far contains

____o_

And you guess y

On the first letter new should equal _

So because y is not the first letter the if clause is false
so the else is selected and new[0] becomes so_far[0], ie '_'
new = '_'

Now on the next index i = 1
guess == word[1] is true
so the if part executes setting new[1] to guess (ie to 'y')
new now equals '_y'

Now on the next index i = 2
guess == word[2] is false so the el;se gets selected
setting new[2] to so_far[2] = '_'
new now equals '_y_'

and so on.

new[i] either acquires the value of guess or so_far[i]
(remember that guess may appear more than once...)

>         so_far = new

Finally so_far is replaced with the final value of new.

There are arguably easier ways of doing this using lists
of characters rather than strings but this works.

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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