Integer Type Checking

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

Is it possible to determine if a scalar variable is an integer or a string?

In a shell script I am porting:

expr $VAR + 1;
if [ $? -ne 0 ]; then 
   do stuff...
fi
[download]

was used to check to see if the value of the variable was an integer.

Is there a similar way to do this in Perl?

Thanks

Comment on Integer Type Checking Download Code

Replies are listed 'Best First'.
Re: Integer Type Checking by insensate (Hermit) on Jul 19, 2002 at 17:37 UTC
Remember... -6 is an integer...and in some cases you may want +5 to be one too...so `print "Integer!" if /^[+-]?\d+$/;` [download] Jason	[reply] [d/l]
Re: Integer Type Checking by mkmcconn (Chaplain) on Jul 19, 2002 at 18:38 UTC
For more reliable type checking, there is Data::Types "This module exports a number of functions that are useful for validating and converting data types. It is intended for use in applications where data types are more important than they typically are in Perl -- e.g., database applications." mkmcconn P.S. also check out Damian's Attribute::Types	[reply]
Re: Integer Type Checking by Nightblade (Beadle) on Jul 19, 2002 at 17:23 UTC
`if($VAR =~ m/^\d+$/) { # Integer } else { # Not integer }` [download]	[reply] [d/l]
Re: Integer Type Checking by simeon2000 (Monk) on Jul 19, 2002 at 17:26 UTC
Perl doesn't differentiate, AFAIK, between strings and integers as far as the programmer is concerned. One way to tell if it's an integer would be: `print "Integer!" if $VAR =~ /^\d+$/;`.	[reply] [d/l]