Hi Perl Monks,

My interest is to find the mean from a LIST (10.12,14,16,18). The list is to uploaded from a text file (x.txt) with STDIN. So, I have written the following script i.e. mean.pl and the text file x.txt. But I am getting wrong results for number of elements (i.e.17) and mean (i.e. 0). The correct number of elements and mean should be 5 and 14, respectively. Can any perl monk help in this matter? I think my question might be a very silly one to the Perl Monks.

The perl script mean.pl goes like:

#!/usr/bin/perl
use warnings;
print"\n Enter the Filename (x.txt) with Data in List context: ";
$filename = <STDIN>;
chomp$filename;
# open the file, or exit
 unless ( open(FILE, $filename) ) {
 print "Cannot open file \"$filename\"\n\n";
 exit;
 } 
 $list = <FILE>; 
print"\n List= $list\n";
@array=split('',$list); # To convert scalar to array
print"\n Array From the List= @array\n";
$N_elements=@array;     # To count number of elements in array 
print"\n Number of Elements= $N_elements\n";
# Sum of all elements in array:
$sum=0;
$sum=eval join '+',@array;
# Mean of the list:  
$mean=$sum/$N_elements;    # Line 21  
print"\n Mean of the list= $mean\n";
exit;
[download]

Here goes the text file x.txt:

(10,12,14,16,18);

The cmd has shown wrong results:

Enter the Filename (x.txt) with Data in List context: x.txt

 List= (10,12,14,16,18);

 Array From the List= ( 1 0 , 1 2 , 1 4 , 1 6 , 1 8 ) ;

 Number= 17
Use of uninitialized value $sum in division (/) at C:\Users\x\Desktop\
+mean.pl
 line 21, <FILE> line 1.

 Mean of the list= 0
[download]

The correct result should look like:

Enter the Filename (x.txt) with Data in List context: x.txt

 List= (10,12,14,16,18);

 Array From the List= ???

 Number of Elements= 5

 Mean of the list= 14
[download]

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