Question

Working on the hangman program, I need to drop the guessed letter from the string of available letters. First, I tried this:
new_avail=avail[0:ptr-1]+avail[ptr+1:26]
to remove the letter I found at avail[ptr].
This dropped 2 letters. I ended up using
new_avail=avail[0:ptr]+avail[ptr+1:26].
This works, but makes no sense to me. How does it skip a letter when there is no index skipped?

2nd question: If I use indices [0:25] for the alphabet, the last letter 'z' gets dropped. I have to specify [0:26]. Why is that?

Answer 1

When you creating a string from the one you have by using [X:Y], it takes all the symbols from position X (including) to position Y (not including). For example:
s = 'abcd'
str[0:1]=='a'
str[2:4]=='cd'

Answer 2

Thank you

Answer 3

http://openstudy.com/updates/50397bb6e4b09b05dfe36868

Answer 4

http://dpaste.com/792359/