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#1
April 24th, 2008, 07:07 PM
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Stats program
Im doing an exercise in a book, and I dont understand one aspect.
theres a sub mean, which calculates the mean but the sub is called in this line, and i dont understand how it computes, could someone explain how it functions.. the line is Code:
return(mean($lower, $upper)); I understand what return does, and mean, but I dont see how the mean interacts with $lower and $upper. Thanks alot
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#4
April 24th, 2008, 07:30 PM
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this is mean function, it then calls on a line of code I dont know how the code of line works, see below...
Code:
sub mean {
my (@data) = @_;
my $sum;
foreach(@data){
$sum+=$_;
}
return($sum/@data);
}
How does this line of code work??? All i see is 2 variable names next to a mean, and I got a blank, how does the 2 variables work Code:
return(mean($lower, $upper); I KNOW its simple, just another blank! Last edited by drjonesuk : April 24th, 2008 at 07:45 PM.
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#5
April 24th, 2008, 08:44 PM
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Code:
sub mean {
my (@data) = @_;
my $sum;
foreach(@data){
$sum+=$_;
}
return($sum/@data);
}
That's the subroutine. It can receive many values. Doesn't have to be two. The will all be collected in @data. The foreach adds all the values together, then returns the value divided by the number of entries. If you wanted to use that subroutine, you would call it like this: Code:
#!/usr/bin/perl
use strict;
use warnings;
my $value = mean(1,2,3,4);
print "$value\n";
sub mean {
my (@data) = @_;
my $sum;
foreach(@data){
$sum+=$_;
}
return($sum/@data);
}
But you don't have to waste the variable if you don't want to. You could just print the value directly: Code:
print mean(1,2,3,4); And in the same way, you could return that directly from another subroutine. Code:
return mean(1,2,3,4); The two variables are just two numbers they want to average: Code:
#!/usr/bin/perl
use strict;
use warnings;
my $one = 5;
my $two = 10;
print mean($one, $two);
sub mean {
my (@data) = @_;
my $sum;
foreach(@data){
$sum+=$_;
}
return($sum/@data);
}
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