prompting a user for input

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

What is the idiomatic way to prompt for y|yes or n|no as well as including a default answer?

Example:

print "Delete this file?[n]: ";
chomp(my $answer=<STDIN>);
if ($answer=~/^y|yes$/i){
    unlink $file or die $!;
} elsif ($answer=~/^n|no|$/i){
        next;
} else { .....
[download]

While writing this I started to think that this might just be a matter of preference so just in case I'll rephrase the question to what are some examples of better ways to go about doing this task.

prompt?
accept: y,n,yes,no
default: to one of the above
continue with program flow
[download]

I'm trying to get away from using /^y|yes$/i and making everything else no or n

Comment on prompting a user for input Select or Download Code

Replies are listed 'Best First'.
Re: prompting a user for input by Anarion (Hermit) on Nov 04, 2001 at 15:11 UTC
I dont know what is the best way, just an if and else, or if and next, i usually use "do that and next if that" but for what you want yo do your regex is wrong, it should be: `~/^(y\|yes)$/i` [download] Yours match every answer that begins with y or ends with yes, try for example young or eyes. $anarion=\$anarion; s==q^QBY_^=,$_^=$[x7,print	[reply] [d/l]
Re: prompting a user for input by joealba (Hermit) on Nov 04, 2001 at 18:00 UTC
Personally, I like to do something like this: `if ($answer =~ /^y/i) { unlink $file or die $!; } else { next; }` [download] So, the user can type "Y", "yessir", "yep", or anything that starts with y. If it doesn't start with y, they mean no. If you want something more exact, then Anarion gave you the perfect regexp above.	[reply] [d/l]
Re: prompting a user for input by perigeeV (Hermit) on Nov 04, 2001 at 17:50 UTC
Here's some fun; reverse the string and the regex in the statement, eg.: `if ( "" =~ /^\Q$answer/i ) { default() } elsif( "YES" =~ /^\Q$answer/i ) { affirmative() } elsif( "NO" =~ /^\Q$answer/i ) { negative() }` [download] Now the user can type "y", "ye" or "yes". Or if you want you can build a case statement: `SWITCH: { $answer =~ /^yes\|y$/ && do { affirmative(); last SWITCH; }; $answer =~ /^no\|n$/ && do { negative(); last SWITCH; }; default(); }` [download]	[reply] [d/l] [select]
Re: prompting a user for input by staeryatz (Monk) on Nov 04, 2001 at 23:42 UTC
Here's a neat regex I've learned for Y/N: `/(Y(es)?\|N(o)?)/i` [download] this accepts Y, N, Yes, No, and ignores cases.	[reply] [d/l]
Re: Re: prompting a user for input by blakem (Monsignor) on Nov 05, 2001 at 02:14 UTC
You probably want to anchor that at the ends, otherwise 'abcNOdef' and 'blahYblah' will match. Also, the parens around the single char 'o' are unnecessary. `/^(Y(es)?\|No?)$/i` [download] -Blake	[reply] [d/l]
Re: prompting a user for input by s0ttle (Scribe) on Nov 11, 2001 at 20:21 UTC
Looking at: `~/^(y\|yes)$/i` [download] This would be my choice: `~/^(?:y(?:\|es))$/i;` [download] matches y or yes without any regard to case and doesn't store the match in $1 unnecessarily. TMTOWTDI -tengo mas que aprender	[reply] [d/l] [select]


Do you know where your variables are?
	PerlMonks