Write a program in Perl using hash












0















I want to print 2 days back after getting input from user.



Example:



enter a day :
Input : Wednesday

Output : monday


I tried it using hashing with array but can't find result.



%hash=('mon',1,'tue',2,'wed',3);
@arr=keys %hash;









share|improve this question





























    0















    I want to print 2 days back after getting input from user.



    Example:



    enter a day :
    Input : Wednesday

    Output : monday


    I tried it using hashing with array but can't find result.



    %hash=('mon',1,'tue',2,'wed',3);
    @arr=keys %hash;









    share|improve this question



























      0












      0








      0








      I want to print 2 days back after getting input from user.



      Example:



      enter a day :
      Input : Wednesday

      Output : monday


      I tried it using hashing with array but can't find result.



      %hash=('mon',1,'tue',2,'wed',3);
      @arr=keys %hash;









      share|improve this question
















      I want to print 2 days back after getting input from user.



      Example:



      enter a day :
      Input : Wednesday

      Output : monday


      I tried it using hashing with array but can't find result.



      %hash=('mon',1,'tue',2,'wed',3);
      @arr=keys %hash;






      perl






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 21 '18 at 3:31









      jwodder

      33.6k45684




      33.6k45684










      asked Nov 21 '18 at 3:24









      Vishal GuptaVishal Gupta

      245




      245
























          2 Answers
          2






          active

          oldest

          votes


















          4














          Your attempt is backwards. The strings by which you want to search should be the keys of the hash.



          my @days = qw( mon tue wed );
          my %index_of_day = map { $days[$_] => $_, $_ => $_ } 0..$#days;

          defined( my $input = <> )
          or die("Premature EOFn");

          chomp($input);

          my $old_index_of_day = $index_of_day{$input}
          or die("Unrecognized day $inputn");

          my $new_index_of_day = $old_index_of_day - 2;
          $new_index_of_day += @days while $new_index_of_day < 0;

          my $output = $days[$new_index_of_day];





          share|improve this answer


























          • My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

            – ssr1012
            Nov 21 '18 at 4:30











          • Either check if you have a number, or add the number to the map. I did the latter.

            – ikegami
            Nov 21 '18 at 4:38











          • thanks it works fine

            – ssr1012
            Nov 21 '18 at 4:56



















          -1














          Using interactive perl-one liner. Note that it is case sensitive and doesn't print anything if it is not matching the keys of the %hash.



          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: fff


          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Mon
          Sat

          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Tue
          Sun

          $





          share|improve this answer


























          • this is working for (Mon, Tue,Wed) only but not for other days.

            – Vishal Gupta
            Nov 21 '18 at 4:29











          • it works.. please check case sensitivity as stored in the hash..and any extra spaces

            – stack0114106
            Nov 21 '18 at 4:32











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          2 Answers
          2






          active

          oldest

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          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          4














          Your attempt is backwards. The strings by which you want to search should be the keys of the hash.



          my @days = qw( mon tue wed );
          my %index_of_day = map { $days[$_] => $_, $_ => $_ } 0..$#days;

          defined( my $input = <> )
          or die("Premature EOFn");

          chomp($input);

          my $old_index_of_day = $index_of_day{$input}
          or die("Unrecognized day $inputn");

          my $new_index_of_day = $old_index_of_day - 2;
          $new_index_of_day += @days while $new_index_of_day < 0;

          my $output = $days[$new_index_of_day];





          share|improve this answer


























          • My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

            – ssr1012
            Nov 21 '18 at 4:30











          • Either check if you have a number, or add the number to the map. I did the latter.

            – ikegami
            Nov 21 '18 at 4:38











          • thanks it works fine

            – ssr1012
            Nov 21 '18 at 4:56
















          4














          Your attempt is backwards. The strings by which you want to search should be the keys of the hash.



          my @days = qw( mon tue wed );
          my %index_of_day = map { $days[$_] => $_, $_ => $_ } 0..$#days;

          defined( my $input = <> )
          or die("Premature EOFn");

          chomp($input);

          my $old_index_of_day = $index_of_day{$input}
          or die("Unrecognized day $inputn");

          my $new_index_of_day = $old_index_of_day - 2;
          $new_index_of_day += @days while $new_index_of_day < 0;

          my $output = $days[$new_index_of_day];





          share|improve this answer


























          • My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

            – ssr1012
            Nov 21 '18 at 4:30











          • Either check if you have a number, or add the number to the map. I did the latter.

            – ikegami
            Nov 21 '18 at 4:38











          • thanks it works fine

            – ssr1012
            Nov 21 '18 at 4:56














          4












          4








          4







          Your attempt is backwards. The strings by which you want to search should be the keys of the hash.



          my @days = qw( mon tue wed );
          my %index_of_day = map { $days[$_] => $_, $_ => $_ } 0..$#days;

          defined( my $input = <> )
          or die("Premature EOFn");

          chomp($input);

          my $old_index_of_day = $index_of_day{$input}
          or die("Unrecognized day $inputn");

          my $new_index_of_day = $old_index_of_day - 2;
          $new_index_of_day += @days while $new_index_of_day < 0;

          my $output = $days[$new_index_of_day];





          share|improve this answer















          Your attempt is backwards. The strings by which you want to search should be the keys of the hash.



          my @days = qw( mon tue wed );
          my %index_of_day = map { $days[$_] => $_, $_ => $_ } 0..$#days;

          defined( my $input = <> )
          or die("Premature EOFn");

          chomp($input);

          my $old_index_of_day = $index_of_day{$input}
          or die("Unrecognized day $inputn");

          my $new_index_of_day = $old_index_of_day - 2;
          $new_index_of_day += @days while $new_index_of_day < 0;

          my $output = $days[$new_index_of_day];






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 21 '18 at 5:42

























          answered Nov 21 '18 at 3:55









          ikegamiikegami

          265k11178400




          265k11178400













          • My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

            – ssr1012
            Nov 21 '18 at 4:30











          • Either check if you have a number, or add the number to the map. I did the latter.

            – ikegami
            Nov 21 '18 at 4:38











          • thanks it works fine

            – ssr1012
            Nov 21 '18 at 4:56



















          • My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

            – ssr1012
            Nov 21 '18 at 4:30











          • Either check if you have a number, or add the number to the map. I did the latter.

            – ikegami
            Nov 21 '18 at 4:38











          • thanks it works fine

            – ssr1012
            Nov 21 '18 at 4:56

















          My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

          – ssr1012
          Nov 21 '18 at 4:30





          My input is 1 or 2 or 0 or mon however error message popups unrecognized day... What is actual input?

          – ssr1012
          Nov 21 '18 at 4:30













          Either check if you have a number, or add the number to the map. I did the latter.

          – ikegami
          Nov 21 '18 at 4:38





          Either check if you have a number, or add the number to the map. I did the latter.

          – ikegami
          Nov 21 '18 at 4:38













          thanks it works fine

          – ssr1012
          Nov 21 '18 at 4:56





          thanks it works fine

          – ssr1012
          Nov 21 '18 at 4:56













          -1














          Using interactive perl-one liner. Note that it is case sensitive and doesn't print anything if it is not matching the keys of the %hash.



          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: fff


          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Mon
          Sat

          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Tue
          Sun

          $





          share|improve this answer


























          • this is working for (Mon, Tue,Wed) only but not for other days.

            – Vishal Gupta
            Nov 21 '18 at 4:29











          • it works.. please check case sensitivity as stored in the hash..and any extra spaces

            – stack0114106
            Nov 21 '18 at 4:32
















          -1














          Using interactive perl-one liner. Note that it is case sensitive and doesn't print anything if it is not matching the keys of the %hash.



          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: fff


          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Mon
          Sat

          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Tue
          Sun

          $





          share|improve this answer


























          • this is working for (Mon, Tue,Wed) only but not for other days.

            – Vishal Gupta
            Nov 21 '18 at 4:29











          • it works.. please check case sensitivity as stored in the hash..and any extra spaces

            – stack0114106
            Nov 21 '18 at 4:32














          -1












          -1








          -1







          Using interactive perl-one liner. Note that it is case sensitive and doesn't print anything if it is not matching the keys of the %hash.



          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: fff


          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Mon
          Sat

          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Tue
          Sun

          $





          share|improve this answer















          Using interactive perl-one liner. Note that it is case sensitive and doesn't print anything if it is not matching the keys of the %hash.



          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: fff


          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Mon
          Sat

          $ perl -ne 'BEGIN{printf("%s","Enter the input: "); my $inp=<STDIN>; chomp($inp); %hash=('Mon',1,'Tue',2,'Wed',3,'Thu',4,'Fri',5,'Sat',6,'Sun',7); $x=$hash{$inp}-2; $x
          +=7 if $x<1; exit if not exists $hash{$inp}; foreach my $y (keys %hash) { print "$y" if $hash{$y}==$x } ; exit } '
          Enter the input: Tue
          Sun

          $






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 21 '18 at 3:58

























          answered Nov 21 '18 at 3:53









          stack0114106stack0114106

          3,9202420




          3,9202420













          • this is working for (Mon, Tue,Wed) only but not for other days.

            – Vishal Gupta
            Nov 21 '18 at 4:29











          • it works.. please check case sensitivity as stored in the hash..and any extra spaces

            – stack0114106
            Nov 21 '18 at 4:32



















          • this is working for (Mon, Tue,Wed) only but not for other days.

            – Vishal Gupta
            Nov 21 '18 at 4:29











          • it works.. please check case sensitivity as stored in the hash..and any extra spaces

            – stack0114106
            Nov 21 '18 at 4:32

















          this is working for (Mon, Tue,Wed) only but not for other days.

          – Vishal Gupta
          Nov 21 '18 at 4:29





          this is working for (Mon, Tue,Wed) only but not for other days.

          – Vishal Gupta
          Nov 21 '18 at 4:29













          it works.. please check case sensitivity as stored in the hash..and any extra spaces

          – stack0114106
          Nov 21 '18 at 4:32





          it works.. please check case sensitivity as stored in the hash..and any extra spaces

          – stack0114106
          Nov 21 '18 at 4:32


















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