Re: Nested foreach loops

Perhaps something like this (You need to provide the 'distance' sub):

use strict;
use warnings;

my (@gsm_site, @umts_site);

while (<DATA>) {
   my ($name1,$lon1,$lat1, $name2,$lon2,$lat2) = split /[\s"]*,["\s]*/
+, $_;
   
    next unless $lat1 and $lon1; # Avoid title lines
    push @gsm_site, {NAME=>$name1, LAT=>$lat1, LON=>$lon1};   
    push @umts_site,{NAME=>$name2, LAT=>$lat2, LON=>$lon2};
}

for my $g (@gsm_site){
      $g->{NEAREST}         =  $umts_site[0]; # Initial assumption til
+l we know better
      $g->{DIST_TO_NEAREST} = distance($g->{LAT},$g->{LON}, $g->{NEARE
+ST}{LAT},$g->{NEAREST}{LON}, "K");
      for my $u (@umts_site[1..$#umts_site]){
         my $this_distance = distance($g->{LAT},$g->{LON}, $u->{LAT},$
+u->{LON}, "K");
         next unless $this_distance < $g->{DIST_TO_NEAREST};
         $g->{NEAREST} = $u;
         $g->{DIST_TO_NEAREST} = $this_distance;
      }
}

# Print them out
for my $g (@gsm_site){
   print "$g->{NAME}, $g->{NEAREST}->{NAME}, $g->{DIST_TO_NEAREST},\n"
+;
}


__DATA__
NameA Longitude Latitude NameB Longitude Latitude 
10001_NI0001, 36.79887354, -1.26122956, " WL3762", 34.52328889 , -1.00
+7941667
NI0006, 36.86998613, -1.295393144, " NM5286", 36.83137418, -1.17262637
+2
NI0066, 36.82748524, -1.25734101, " EC4140", 37.4580536, -0.53351668,
[download]

Note - you should really use a module like Text::CSV, instead of the split hack, above.

...it is unhealthy to remain near things that are in the process of blowing up. man page for WARP, by Larry Wall

Comment on Re: Nested foreach loops Download Code

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Re^2: Nested foreach loops by keienn (Novice) on Sep 09, 2016 at 22:06 UTC
Thank you Monks, for your great help. I did try NetWallah's code,thanks O great Abbot. I am however getting some errors originating from the subroutine which am sharing here as you had suggested. I previously got such errors while trying different loops but avoided tinkering with the subroutine which works as it is. What should i change in the new code? Here are the exceptions am getting and the subroutine code; The errors, the line 5852 is the last line in my CSV file C:\MyScripts\2G3Gdistance.pl Argument "Longitude" isn't numeric in subtraction (-) at C:\MyScripts\2G3Gdistance.pl line 53, <COMBINED> line 5852 (#1) Argument "Latitude" isn't numeric in multiplication () at C:\MyScripts\2G3Gdistance.pl line 80, <COMBINED> line 5852 (#1) Use of uninitialized value $lon2 in subtraction (-) at C:\MyScripts\2G3Gdistance.pl line 53, <COMBINED> line 5852 (#2) (W uninitialized) An undefined value was used as if it were already defined. It was interpreted as a "" or a 0, but maybe it was a mistake. To suppress this warning assign a defined value to your variables. Use of uninitialized value $deg in multiplication () at C:\MyScripts\2G3Gdistance.pl line 80, <COMBINED> line 5852 (#2) Uncaught exception from user code: Can't take sqrt of -4.44089e-016 at C:\MyScripts\2G3Gdistance.pl line 71, <COMBINED> line 5852. main::acos(1) called at C:\MyScripts\2G3Gdistance.pl line 55 main::distance(-0.433525648, 36.968599085, -0.433525648, 36.96859909, "K") called at C:\MyVolume\Development\MyScripts\2G3Gdistance.pl line 150 The subroutine code my $pi = atan2(1,1) * 4; sub distance { my ($lat1, $lon1, $lat2, $lon2, $unit) = @_; my $theta = $lon1 - $lon2; my $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) + cos(deg2rad +($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta)); $dist = acos($dist); $dist = rad2deg($dist); $dist = $dist * 60 * 1.1515; if ($unit eq "K") { $dist = $dist * 1.609344; } elsif ($unit eq "N") { $dist = $dist * 0.8684; } return ($dist); } #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: #::: This function get the arccos function using arctan function :: +: #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: sub acos { my ($rad) = @_; my $ret = atan2(sqrt(1 - $rad*2), $rad); return $ret; } #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: #::: This function converts decimal degrees to radians :: +: #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: sub deg2rad { my ($deg) = @_; return ($deg $pi / 180); } #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: #::: This function converts radians to decimal degrees :: +: #::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: +: sub rad2deg { my ($rad) = @_; return ($rad * 180 / $pi); } print distance(32.9697, -96.80322, 29.46786, -98.53506, "K") . " Kilom +eters\n"; [download]	[reply] [d/l]
Re^3: Nested foreach loops by hippo (Bishop) on Sep 10, 2016 at 08:51 UTC
`Argument "Longitude" isn't numeric in subtraction (-) at C:\MyScripts\ +2G3Gdistance.pl line 53, <COMBINED> line 5852 (#1) Argument "Latitude" isn't numeric in multiplication () at C:\MyScript +s\2G3Gdistance.pl line 80, <COMBINED> line 5852 (#1)` [download] These are clearly the results of you trying to perform arithmetic on the values obtained from your data file's header row. Don't do that. Only start processing the actual data from row 2 onwards. `Use of uninitialized value $lon2 in subtraction (-) at C:\MyScripts\2G3Gdistance.pl line 53, <COMBINED> line 5852 (#2)`* This suggests that you have not parsed the data file correctly because `$lon2` remains undefined. I suggest that you print out the values of all the arguments to `distance()` as soon as you retrieve them in order to determine how the parsing has failed and then correct that. The later errors are likely propagations of this problem. Do take a look through the Basic debugging checklist if you have not already done so. It will help you clear up such similar problems in future.	[reply] [d/l] [select]
Re^4: Nested foreach loops by keienn (Novice) on Sep 17, 2016 at 22:10 UTC
Great Monks I finally did get the code to give the solution I wanted. It still gives the 'uninitialized value' warnings which i have suppressed, but i now know they come about because of the empty cells in the CSV file being used in a calculation. These I will deal with eventually.	[reply]


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