saving and loading variables to/from a file

paulterack

Can someone suggest the best way to save and load variables with files in PERL? I have to admit I'm furstrated- I know just how "I" would do it in C/C++, but PERL is new to me. Here's what I'm looking for:

THere'd be a series of these, i.e. an array of this type that had both a counter name and associated value.

First I need a way to create the following:

Counter[0]->name = "main counter"
Counter[0]->value = 4587
Counter[1]->name = "free site"
Counter[1]->value = 10562

I'm not sure how to create a "user defined" type array like I have above in PERL.

Second a way to save this and then re-load it. I can read text from a file, but I can't figure out how to "parse" it into the appropriate variables.

I'm happy to help with any questions you may have on C/C++ or VB development- I'm well versed in those areas, but need some help with PERL.

thanks a lot,
-Andrew

KevinADC

My C/C++ knowledge == 0, but I think what you are after is a named hash:

%Counter = (
'main counter' => 4587,
'free site' => 10562
);

You access the values like so:

$Counter{'main counter'}
$Counter{'free site'}

You have to quote the key names because they have spaces in them.
If you wanted to increment them just use the standard ++

$Counter{'main counter'}++; (now equals 4588)

if you had to find the correct value to increment and had the key name alreay in a variable:

$string = 'main counter';
$Counter{$string}++

and so on

Jonathan

: Can someone suggest the best way to save and load variables with files in PERL? I have to admit I'm furstrated- I know just how "I" would do it in C/C++, but PERL is new to me. Here's what I'm looking for:
:
: THere'd be a series of these, i.e. an array of this type that had both a counter name and associated value.
:
: First I need a way to create the following:
:
: Counter[0]->name = "main counter"
: Counter[0]->value = 4587
: Counter[1]->name = "free site"
: Counter[1]->value = 10562
:
: I'm not sure how to create a "user defined" type array like I have
: above in PERL.
:
Use a hash data structure to map names to values, then hold an array of hashes. Note that you don't specify the keys "up front" like in a struct.

# Create array.
my @counter;

# Initialise each array entry to an empty hash
$counter[$_] = {} for 0..1;

# Store stuff like this:-
$counter[0]->{name} = "main counter";
$counter[0]->{value} = 123;
# etc

: Second a way to save this and then re-load it. I can read text from a
: file, but I can't figure out how to "parse" it into the appropriate
: variables.
:
The easiest way to store a complex data structure of any kind is to serialize it. Check out the Storable module.
http://search.cpan.org/~ams/Storable-2.13/Storable.pm

: I'm happy to help with any questions you may have on C/C++ or VB
: development- I'm well versed in those areas, but need some help with
: PERL.
:
You're coming from a bunch of statically typed languages to a dynamically typed one. That alone may feel weird for a while. :-)

Jonathan

###
for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
(tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
/(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");

paulterack

: : Can someone suggest the best way to save and load variables with files in PERL? I have to admit I'm furstrated- I know just how "I" would do it in C/C++, but PERL is new to me. Here's what I'm looking for:
: :
: : THere'd be a series of these, i.e. an array of this type that had both a counter name and associated value.
: :
: : First I need a way to create the following:
: :
: : Counter[0]->name = "main counter"
: : Counter[0]->value = 4587
: : Counter[1]->name = "free site"
: : Counter[1]->value = 10562
: :
: : I'm not sure how to create a "user defined" type array like I have
: : above in PERL.
: :
: Use a hash data structure to map names to values, then hold an array of hashes. Note that you don't specify the keys "up front" like in a struct.
:
: # Create array.
: my @counter;
:
: # Initialise each array entry to an empty hash
: $counter[$_] = {} for 0..1;
:
: # Store stuff like this:-
: $counter[0]->{name} = "main counter";
: $counter[0]->{value} = 123;
: # etc
:
: : Second a way to save this and then re-load it. I can read text from a
: : file, but I can't figure out how to "parse" it into the appropriate
: : variables.
: :
: The easiest way to store a complex data structure of any kind is to serialize it. Check out the Storable module.
: http://search.cpan.org/~ams/Storable-2.13/Storable.pm
:
: : I'm happy to help with any questions you may have on C/C++ or VB
: : development- I'm well versed in those areas, but need some help with
: : PERL.
: :
: You're coming from a bunch of statically typed languages to a dynamically typed one. That alone may feel weird for a while. :-)
:
: Jonathan
:
: ###
: for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
: (tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
: /(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");
:
:

THanks so much, that's a lot of great information, I really appreciate it.

-Andrew