in reply to Search a hash for STDIN and report findings

As a first step, provide an example that compiles. Your example has too many opening and too few closing curly braces.

foreach ($input)

There's no need for a foreach loop over one element, so leave that out.

I rewrote your example in a way that I think you intended: 

use strict;
use warnings;

my %passwords = (
        moritz => 'secret',
    );

while(<STDIN>) {
    chomp;
    if (exists $passwords{$_}){
        print "Password from $_ is '$passwords{$_}'\n";
    } else {
        print "No password for $_, sorry\n";
    }
}

[download]

And this is how a run could look like: 

$ perl script.pl
moritz
Password from moritz is 'secret'
someone else
No password for someone else, sorry

[download]

Replies are listed 'Best First'.
Re^2: Search a hash for STDIN and report findings
by trenchwar (Beadle) on Feb 07, 2008 at 18:51 UTC
    Definitely better. I have put the entire little script below. The user name is formatted and stored in a hash key with the password as the value. I want to then have the user put in a first or last name and have it searched against the hash and return the user name and pass word if it is found..problem I am having is case sensitivity. Please pardon my useless script, I am trying to learn Perl. 
    
while(1)
{
        print "Please enter your first name\n";
        chomp ($fname =<STDIN>);
           {
                last;
           }
        print "Please enter your last name\n";
        chomp ($lname =<STDIN>);
           {
                last;
           }
        print "Please enter a password\n";
        chomp ($password =<STDIN>);
           {
                last;
           }
        print "Please enter 'done' or hit your return key\n";
        chomp ($ending =<STDIN>);
        if ($ending eq '\n' or 'done')
           {
                last;
           }
}

my $username = "$lname, $fname";
%new_hash;
$new_hash{$username} = $password;

print "To search for a user please type in the last name, firstname an
+d hit enter.\n";

while(<STDIN>) {
    chomp;
    if (exists $new_hash{$_}){
        print "The username is $username and the password is $password
+, please enter another name to search for.\n";
    } else {
        print "I'm sorry, there is no one here by that name please try
+ again.\n";
        }
}

    [download]
    Thank you! TW
[reply]
[d/l]
      One problem is that your hash is empty after you tried to enter the values - there is no assignment to the hash.

      If you want to know the values of your hash, here's a little trick: 

      use Data::Dumper;
my %passwords; # please don't name your data structure
               # %new_hash. That's not a telling name at 
               # all
while(1)
{
        print "Please enter your first name\n";
        chomp ($fname =<STDIN>);
           {
                last;
           }
        print "Please enter your last name\n";
        chomp ($lname =<STDIN>);
           {
                last;
           }
        print "Please enter a password\n";
        chomp ($password =<STDIN>);
           {
                last;
           }
        print "Please enter 'done' or hit your return key\n";
        chomp ($ending =<STDIN>);
        if ($ending eq '\n' or 'done')
           {
                last;
           }
}

my $username = "$lname, $fname";

# here comes the magic:
print Dumper \%passwords; # you'll see that the hash 
                          # is empty.

# rest of the script goes here

      [download]

      You have to actually store the passwords: 

      while(1)
{
        print "Please enter your first name\n";
        chomp ($fname =<STDIN>);
           {
                last;
           }
        print "Please enter your last name\n";
        chomp ($lname =<STDIN>);
           {
                last;
           }
        print "Please enter a password\n";
        chomp ($password =<STDIN>);
           {
                last;
           }
        # important: store the passwords in %passwords
        $passwords{$fname} = $password;

        print "Please enter 'done' or hit your return key\n";
        chomp ($ending =<STDIN>);
        if ($ending eq '\n' or 'done')
           {
                last;
           }
}

      [download]

      Additionally the usual tips apply: always use strict; use warnings and declare your variables.

      To answer your original question: to achieve case insensitivity, use lc or uc to convert the strings (for example first name) to all lower or all upper case, and only then store them.

[reply]
[d/l]
[select]
        you guys probably want 
        if ($ending eq '\n' or 'done')

        [download]

        to be 

        if ( ($ending eq '\n') or ($ending eq 'done') )

        [download]
[reply]
[d/l]
[select]
        Thank you for your infinite patiences
[reply]

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