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Increment variable with leading zero's

Increment variable with leading zero's

Post by Dave » Thu, 13 Oct 2005 04:20:39



Using the following snippet of scipt as an example, how do I increment
my variable without loosing the leading zero?

  MyVar=00
  while [ $MyVar -lt 20]
  do
    echo "MyVar is $MyVar"
    MyVar=`expr MyVar + 1 `
  done

I would like to see an output of:
 00
 01
 02 ...
 10
 11
 12 ...
 19

But what I see is:
 00
 1
 2 ...
 10
 11 ...
 19

Any suggestions?  I am willing to use a different shell and I am open
to using sed or awk.  

Thanks

Dave

 
 
 
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Increment variable with leading zero's

Post by Janis Papanagno » Thu, 13 Oct 2005 04:35:01



> Using the following snippet of scipt as an example, how do I increment
> my variable without loosing the leading zero?

>   MyVar=00
>   while [ $MyVar -lt 20]
>   do
>     echo "MyVar is $MyVar"
>     MyVar=`expr MyVar + 1 `
>   done

> Any suggestions?  I am willing to use a different shell and I am open
> to using sed or awk.  

If you are willing to use ksh93...

     typeset -Z2 MyVar=0
     for (( MyVar=0 ; MyVar < 20 ; MyVar++ ))
     do
         echo "MyVar is $MyVar"
     done

Janis

 
 
 
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Increment variable with leading zero's

Post by Janis Papanagno » Thu, 13 Oct 2005 04:39:28



> Using the following snippet of scipt as an example, how do I increment
> my variable without loosing the leading zero?

>   MyVar=00
>   while [ $MyVar -lt 20]
>   do
>     echo "MyVar is $MyVar"
>     MyVar=`expr MyVar + 1 `
>   done

> Any suggestions?  I am willing to use a different shell and I am open
> to using sed or awk.  

If you are willing to use ksh93 or bash...

     for (( MyVar=0 ; MyVar < 20 ; MyVar++ ))
     do
         printf "MyVar is %02d\n" "$MyVar"
     done

Janis

 
 
 
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Increment variable with leading zero's

Post by Stephane CHAZELA » Thu, 13 Oct 2005 05:14:20


2005-10-11, 21:35(+02), Janis Papanagnou:

>> Using the following snippet of scipt as an example, how do I increment
>> my variable without loosing the leading zero?

>>   MyVar=00
>>   while [ $MyVar -lt 20]
>>   do
>>     echo "MyVar is $MyVar"
>>     MyVar=`expr MyVar + 1 `
>>   done

>> Any suggestions?  I am willing to use a different shell and I am open
>> to using sed or awk.  

> If you are willing to use ksh93...

>      typeset -Z2 MyVar=0
>      for (( MyVar=0 ; MyVar < 20 ; MyVar++ ))
>      do
>          echo "MyVar is $MyVar"
>      done

[...]

Not only ksh93. Also zsh, ksh88 and pdksh for -Z2 and zsh for
the for (( ... )).

--
Stphane

 
 
 
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Increment variable with leading zero's

Post by Erik Max Franci » Thu, 13 Oct 2005 05:53:31



> Any suggestions?  I am willing to use a different shell and I am open
> to using sed or awk.  

man printf

--

San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
   In time of war the devil makes more room in hell.
   -- (a German proverb)

 
 
 
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Increment variable with leading zero's

Post by Dave » Thu, 13 Oct 2005 06:38:12


Thanks for the help everybody!  I learned a few new things today.
 
 
 
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Increment variable with leading zero's

Post by John W. Krah » Thu, 13 Oct 2005 09:45:33



> Using the following snippet of scipt as an example, how do I increment
> my variable without loosing the leading zero?

>   MyVar=00
>   while [ $MyVar -lt 20]
>   do
>     echo "MyVar is $MyVar"
>     MyVar=`expr MyVar + 1 `
>   done

> I would like to see an output of:
>  00
>  01
>  02 ...
>  10
>  11
>  12 ...
>  19

> But what I see is:
>  00
>  1
>  2 ...
>  10
>  11 ...
>  19

> Any suggestions?  I am willing to use a different shell and I am open
> to using sed or awk.  

You could do it in perl:

$ perl -e'
$MyVar = "00";
while ( $MyVar lt "20" ) {
    print "MyVar is $MyVar\n";
    $MyVar++;
    }
'
MyVar is 00
MyVar is 01
MyVar is 02
MyVar is 03
...
MyVar is 16
MyVar is 17
MyVar is 18
MyVar is 19

Or:

$ perl -e'
for $MyVar ( "00" .. "20" ) {
    print "MyVar is $MyVar\n";
    }
'
MyVar is 00
MyVar is 01
MyVar is 02
MyVar is 03
...
MyVar is 16
MyVar is 17
MyVar is 18
MyVar is 19

John
--
use Perl;
program
fulfillment

 
 
 
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Increment variable with leading zero's

Post by Chris F.A. Johnso » Thu, 13 Oct 2005 10:24:10



> Using the following snippet of scipt as an example, how do I increment
> my variable without loosing the leading zero?

>   MyVar=00
>   while [ $MyVar -lt 20]
>   do
>     echo "MyVar is $MyVar"
>     MyVar=`expr MyVar + 1 `
>   done

> I would like to see an output of:
>  00
>  01
>  02 ...
>  10
>  11
>  12 ...
>  19

> But what I see is:
>  00
>  1
>  2 ...
>  10
>  11 ...
>  19

> Any suggestions?  I am willing to use a different shell and I am open
> to using sed or awk.  

   In any POSIX shell:

MyVar=0
while [ $MyVar -lt 20 ]
do
    printf "MyVar is %02d\n" "$MyVar"
    MyVar=$(( $MyVar + 1 ))
done

   In awk:

awk 'BEGIN { while (MyVar < 20 ) printf "MyVar is %02d\n", MyVar++; exit }'

   In bash version 3:

printf "MyVar is %02d\n" {0..19}

   In William Park's extended bash:

printf "MyVar is %s\n" {00..19}

--
    Chris F.A. Johnson                     <http://cfaj.freeshell.org>
    ==================================================================
    Shell Scripting Recipes: A Problem-Solution Approach, 2005, Apress
    <http://www.torfree.net/~chris/books/cfaj/ssr.html>

 
 
 
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Increment variable with leading zero's

Post by Stephane CHAZELA » Thu, 13 Oct 2005 05:18:10


2005-10-11, 21:39(+02), Janis Papanagnou:

>> Using the following snippet of scipt as an example, how do I increment
>> my variable without loosing the leading zero?

>>   MyVar=00
>>   while [ $MyVar -lt 20]
>>   do
>>     echo "MyVar is $MyVar"
>>     MyVar=`expr MyVar + 1 `
>>   done

>> Any suggestions?  I am willing to use a different shell and I am open
>> to using sed or awk.  

> If you are willing to use ksh93 or bash...

>      for (( MyVar=0 ; MyVar < 20 ; MyVar++ ))
>      do
>          printf "MyVar is %02d\n" "$MyVar"
>      done

[...]

Or zsh.

But what's the point of advertising non-standard syntaxes, when
the standard ones work just as well:

MyVar=0
while [ "$MyVar" -lt 20 ]
do
  printf 'MyVar is %02d\n' "$MyVar"
  MyVar=$(($MyVar + 1))
esac

zsh:

print -l "MyVar is "{00..19}

;)

--
Stphane

 
 
 
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Increment variable with leading zero's

Post by Gran » Thu, 13 Oct 2005 16:45:08



>But what's the point of advertising non-standard syntaxes, when
>the standard ones work just as well:

>MyVar=0
>while [ "$MyVar" -lt 20 ]
>do
>  printf 'MyVar is %02d\n' "$MyVar"
>  MyVar=$(($MyVar + 1))
>esac

s/esac/done/ ??  
Quote:

>zsh:

>print -l "MyVar is "{00..19}

>;)

 
 
 
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Increment variable with leading zero's

Post by Janis Papanagno » Fri, 14 Oct 2005 01:34:19



> But what's the point of advertising non-standard syntaxes, when
> the standard ones work just as well:

A clearer syntax and the OP's statement "I am willing to use a
different shell".

YMMV.

Janis

 
 
 
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