Mean and standard deviation loop

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

Hi All, Please help l am still a Perl novice and cant get my head around this loop l need to write in order to create a new text file with the mean and standard deviation from ranges in a csv file. Here is an example of the file:

Col1,Col2,Col3,Col4,Col5,Col6
Name 1,IGNORE,ID 1,0.37982135,0.791818317,0.652424768
Name 1,IGNORE,ID 1,0.721513387,0.881438903,0.460097013
Name 1,IGNORE,ID 1,0.804540751,0.30103416,0.307076201
Name 1,IGNORE,ID 1,0.244148341,0.665789239,0.073428582
Name 1,IGNORE,ID 2,0.425204974,0.830647697,0.026222533
Name 1,IGNORE,ID 2,0.64290764,0.506440565,0.593350606
Name 1,IGNORE,ID 2,0.299279085,0.279361006,0.639529638
Name 1,IGNORE,ID 2,0.696625882,0.910134661,0.462723154
Name 1,IGNORE,ID 2,0.775977962,0.972299177,0.574419934
Name 1,IGNORE,ID 2,0.145839987,0.785302378,0.856054519
Name 1,IGNORE,ID 2,0.380588138,0.184563257,0.614053111
Name 1,IGNORE,ID 2,0.657711661,0.960401631,0.687047718
Name 1,IGNORE,ID 3,0.50094279,0.244414627,0.027866195
Name 1,IGNORE,ID 3,0.247070699,0.329813346,0.72012615
Name 1,IGNORE,ID 3,0.528465719,0.519431152,0.380683376
Name 1,IGNORE,ID 3,0.001334767,0.772583548,0.283821376
Name 1,IGNORE,ID 3,0.035444487,0.177265159,0.65665088
Name 1,IGNORE,ID 3,0.390519351,0.614277413,0.115720898
Name 1,IGNORE,ID 3,0.290907022,0.623986491,0.114367918
Name 1,IGNORE,ID 3,0.960698899,0.282528688,0.789410834
Name 2,IGNORE,ID 1,0.52029931,0.217956687,0.034778849
Name 2,IGNORE,ID 1,0.390883709,0.433090757,0.834412219
Name 2,IGNORE,ID 1,0.969661816,0.256131736,0.382298203
Name 2,IGNORE,ID 1,0.182221598,0.50228435,0.273815182
Name 2,IGNORE,ID 1,0.155900495,0.164124636,0.121096495
Name 2,IGNORE,ID 1,0.877336374,0.673715671,0.381463711
Name 2,IGNORE,ID 2,0.132989121,0.275819298,0.522132919
Name 2,IGNORE,ID 2,0.566069681,0.778573666,0.577410397
Name 2,IGNORE,ID 2,0.861289328,0.751731334,0.895456821
Name 2,IGNORE,ID 2,0.601763435,0.054547388,0.422025303
Name 2,IGNORE,ID 2,0.239323207,0.026933112,0.345341484
Name 2,IGNORE,ID 2,0.785210274,0.031020763,0.043997356
Name 2,IGNORE,ID 2,0.849328727,0.159601291,0.006723201
Name 2,IGNORE,ID 2,0.882972537,0.839234269,0.11965987
Name 2,IGNORE,ID 2,0.114967039,0.467529515,0.325535197
Name 2,IGNORE,ID 3,0.219825579,0.776021711,0.887957411
Name 2,IGNORE,ID 3,0.615890229,0.846215519,0.808795755
Name 2,IGNORE,ID 3,0.382284625,0.649516417,0.164323894
Name 2,IGNORE,ID 3,0.932202153,0.954362672,0.709015286
Name 2,IGNORE,ID 3,0.159515113,0.417265005,0.14523904
Name 2,IGNORE,ID 3,0.57268037,0.289845554,0.052907578
Name 2,IGNORE,ID 3,0.236739875,0.844689238,0.728153225
Name 2,IGNORE,ID 3,0.335484964,0.608410584,0.165027002
Name 2,IGNORE,ID 3,0.115758212,0.377994434,0.22737545
Name 2,IGNORE,ID 3,0.58695053,0.192963069,0.48771977
Name 2,IGNORE,ID 4,0.501302506,0.379030488,0.870477352
Name 2,IGNORE,ID 4,0.808307454,0.842780413,0.786997964
Name 2,IGNORE,ID 4,0.269026636,0.284492031,0.773855038
Name 2,IGNORE,ID 4,0.700413158,0.10286498,0.523411249
Name 2,IGNORE,ID 4,0.118227472,0.284542899,0.793854806
Name 2,IGNORE,ID 4,0.512343377,0.319557477,0.53841837
Name 2,IGNORE,ID 4,0.819964968,0.879054472,0.765823587
Name 2,IGNORE,ID 4,0.86335164,0.475113054,0.627558806
Name 2,IGNORE,ID 4,0.750244582,0.613032699,0.182777923
Name 2,IGNORE,ID 4,0.275165823,0.021067739,0.612086553
Name 2,IGNORE,ID 4,0.226488906,0.635489023,0.747917162
Name 2,IGNORE,ID 4,0.488732866,0.587405833,0.412799804
Name 2,IGNORE,ID 4,0.596252248,0.56288024,0.923117578
Name 2,IGNORE,ID 4,0.315232094,0.905375958,0.640880331
Name 2,IGNORE,ID 4,0.419892207,0.501447283,0.841059496
Name 2,IGNORE,ID 5,0.027954045,0.603952859,0.179546933
Name 2,IGNORE,ID 5,0.203437218,0.832374684,0.332714406
Name 2,IGNORE,ID 5,0.492690906,0.490600928,0.718792343
Name 2,IGNORE,ID 5,0.761181274,0.866338049,0.315125996
Name 2,IGNORE,ID 5,0.968684085,0.465075264,0.453525826
Name 2,IGNORE,ID 5,0.965926406,0.511947021,0.63041369
Name 2,IGNORE,ID 5,0.830650173,0.145010257,0.854201445
Name 2,IGNORE,ID 5,0.740655024,0.496291265,0.965611823
Name 2,IGNORE,ID 5,0.594504215,0.320318337,0.460041343
Name 2,IGNORE,ID 5,0.469701381,0.346615537,0.729423429
Name 2,IGNORE,ID 5,0.364647905,0.912741612,0.200696706
Name 2,IGNORE,ID 5,0.650916143,0.143698107,0.71461251
Name 2,IGNORE,ID 5,0.236520771,0.846877843,0.47651797
Name 2,IGNORE,ID 5,0.83696323,0.886732329,0.7868661
Name 2,IGNORE,ID 5,0.048179463,0.302861896,0.942740508
Name 2,IGNORE,ID 5,0.561141223,0.157787635,0.921377274
Name 2,IGNORE,ID 6,0.054753633,0.496822999,0.426184382
Name 2,IGNORE,ID 6,0.392287968,0.089318893,0.410990992
Name 2,IGNORE,ID 6,0.219582733,0.287663836,0.033101737
Name 2,IGNORE,ID 6,0.666103181,0.505495999,0.728609282
Name 2,IGNORE,ID 6,0.997576553,0.135051446,0.523997905
Name 2,IGNORE,ID 6,0.440280551,0.320183615,0.134193205
Name 2,IGNORE,ID 6,0.46226184,0.208013033,0.865425765
Name 2,IGNORE,ID 6,0.869363826,0.301666045,0.763282357
Name 2,IGNORE,ID 6,0.986298107,0.665474133,0.924482868
Name 2,IGNORE,ID 6,0.130406143,0.924405695,0.390965551
Name 2,IGNORE,ID 6,0.941576004,0.40262737,0.232998427
Name 2,IGNORE,ID 6,0.557452214,0.826768069,0.009160847
Name 2,IGNORE,ID 6,0.713443893,0.167423963,0.880938869
Name 2,IGNORE,ID 6,0.070524667,0.223616125,0.402114973
Name 2,IGNORE,ID 6,0.210950729,0.127250272,0.659798497
Name 3,IGNORE,ID 1,0.331583378,0.05338106,0.128834081
Name 3,IGNORE,ID 1,0.690538179,0.789946028,0.945991209
Name 3,IGNORE,ID 1,0.165157277,0.998774239,0.0455421
Name 3,IGNORE,ID 1,0.605826929,0.080406226,0.126499074
Name 3,IGNORE,ID 1,0.956784451,0.311633382,0.47904799
Name 3,IGNORE,ID 1,0.032108824,0.914251623,0.465807797
Name 3,IGNORE,ID 1,0.209457389,0.803181549,0.359003069
Name 3,IGNORE,ID 1,0.53235704,0.855123438,0.304031395
Name 3,IGNORE,ID 2,0.976087028,0.327735368,0.529816747
Name 3,IGNORE,ID 2,0.678639311,0.704008305,0.186024057
Name 3,IGNORE,ID 2,0.95579316,0.946794771,0.093978138
Name 3,IGNORE,ID 2,0.535135211,0.616836963,0.555452335
Name 3,IGNORE,ID 2,0.353519383,0.743495309,0.73279098
Name 3,IGNORE,ID 2,0.692094099,0.376559244,0.008859322
Name 3,IGNORE,ID 2,0.36585992,0.378740255,0.7876411
Name 3,IGNORE,ID 2,0.013224478,0.496042768,0.034245886
Name 3,IGNORE,ID 2,0.376288745,0.562422774,0.889485667
Name 3,IGNORE,ID 2,0.507718223,0.413729714,0.893780487
Name 3,IGNORE,ID 2,0.086020289,0.575655064,0.478651028
Name 3,IGNORE,ID 3,0.714735222,0.061739536,0.417562291
Name 3,IGNORE,ID 3,0.831754648,0.223515306,0.070781154
Name 3,IGNORE,ID 3,0.231560448,0.075462932,0.196199016
Name 3,IGNORE,ID 3,0.888036581,0.657571916,0.020372209
Name 3,IGNORE,ID 3,0.500038109,0.735243357,0.21473527
Name 3,IGNORE,ID 3,0.269553886,0.92740133,0.579772528
Name 3,IGNORE,ID 3,0.262827679,0.690383144,0.779901605
Name 3,IGNORE,ID 3,0.560589794,0.828025582,0.507173871
Name 3,IGNORE,ID 3,0.02545088,0.057554697,0.533111624
Name 3,IGNORE,ID 3,0.181576318,0.943676799,0.133749761
Name 3,IGNORE,ID 3,0.202273952,0.117622017,0.614573059
Name 3,IGNORE,ID 3,0.658081544,0.396384996,0.251594415
Name 3,IGNORE,ID 3,0.666397989,0.627433713,0.192909205
Name 3,IGNORE,ID 4,0.834378245,0.93129209,0.482303893
Name 3,IGNORE,ID 4,0.435969447,0.964872927,0.409713174
Name 3,IGNORE,ID 4,0.315667797,0.741551553,0.724828033
Name 3,IGNORE,ID 4,0.441599787,0.387304774,0.932125435
Name 3,IGNORE,ID 4,0.132473891,0.397548401,0.769881268
Name 3,IGNORE,ID 4,0.656655881,0.491286593,0.736728362
Name 3,IGNORE,ID 4,0.714934678,0.939271723,0.424204648
Name 3,IGNORE,ID 4,0.28152302,0.238264583,0.403745356
Name 3,IGNORE,ID 4,0.397335519,0.694688244,0.995862278
Name 3,IGNORE,ID 4,0.803515204,0.016659858,0.686058043
Name 3,IGNORE,ID 4,0.382836019,0.898355202,0.525285486
Name 3,IGNORE,ID 4,0.71194337,0.525643652,0.563393929
Name 3,IGNORE,ID 4,0.425912809,0.950649598,0.83262041
Name 3,IGNORE,ID 5,0.107861783,0.090576382,0.810290528
Name 3,IGNORE,ID 5,0.812035455,0.362919345,0.603067695
Name 3,IGNORE,ID 5,0.875468795,0.288728237,0.716083531
Name 3,IGNORE,ID 5,0.583141247,0.089452692,0.847372685
Name 3,IGNORE,ID 5,0.747409815,0.203152854,0.316762478
Name 3,IGNORE,ID 5,0.148171719,0.305170065,0.002037187
Name 3,IGNORE,ID 5,0.534605619,0.120470186,0.01753885
Name 3,IGNORE,ID 5,0.570773853,0.58967248,0.55075633
Name 3,IGNORE,ID 5,0.213932106,0.748859437,0.017916466
Name 3,IGNORE,ID 5,0.672609412,0.75729189,0.874194686
Name 3,IGNORE,ID 5,0.078913513,0.295277146,0.9605599
Name 3,IGNORE,ID 6,0.161652468,0.256321818,0.291330684
Name 3,IGNORE,ID 6,0.768664648,0.807839215,0.664323076
Name 3,IGNORE,ID 6,0.855204581,0.606592189,0.710802554
Name 3,IGNORE,ID 6,0.282669948,0.193352094,0.714680507
Name 3,IGNORE,ID 6,0.809227298,0.814022818,0.983258816
Name 3,IGNORE,ID 6,0.325573758,0.510825554,0.609916485
Name 3,IGNORE,ID 6,0.374756314,0.997788561,0.184902868
Name 3,IGNORE,ID 6,0.351667219,0.217427335,0.134593906
Name 3,IGNORE,ID 6,0.872674608,0.533825578,0.752141807
Name 3,IGNORE,ID 6,0.321759984,0.798189175,0.645437855
Name 3,IGNORE,ID 6,0.599191186,0.220917242,0.277175086
Name 3,IGNORE,ID 6,0.852745332,0.271589722,0.861608693
Name 3,IGNORE,ID 6,0.628306658,0.852902302,0.520219421
Name 3,IGNORE,ID 7,0.324223654,0.376985921,0.552674926
Name 3,IGNORE,ID 7,0.162620802,0.209952181,0.066167776
Name 3,IGNORE,ID 7,0.688614864,0.674588849,0.343567297
Name 3,IGNORE,ID 7,0.897478871,0.699221782,0.697716567
Name 3,IGNORE,ID 7,0.958406136,0.95946889,0.257582265
Name 3,IGNORE,ID 7,0.66486043,0.315839631,0.265555319
Name 3,IGNORE,ID 7,0.744613767,0.842190349,0.089507978
Name 3,IGNORE,ID 7,0.90787385,0.754901563,0.015983226
Name 3,IGNORE,ID 7,0.463885541,0.98461792,0.11082385
Name 3,IGNORE,ID 7,0.506738303,0.945769999,0.017478177
Name 3,IGNORE,ID 7,0.269568318,0.263827257,0.851695483
Name 3,IGNORE,ID 7,0.138290466,0.802143341,0.983498242
Name 3,IGNORE,ID 7,0.607150506,0.025864193,0.551843394
Name 3,IGNORE,ID 8,0.500603368,0.400331981,0.791633065
Name 3,IGNORE,ID 8,0.605062432,0.067761939,0.367149629
Name 3,IGNORE,ID 8,0.329244606,0.410084524,0.276165148
Name 3,IGNORE,ID 8,0.171468104,0.452224236,0.355038138
Name 3,IGNORE,ID 8,0.50592024,0.482206447,0.248042776
Name 3,IGNORE,ID 8,0.352207588,0.771484409,0.517947243
Name 3,IGNORE,ID 8,0.608753402,0.197817955,0.849418686
Name 3,IGNORE,ID 8,0.584675616,0.4401131,0.522428859
Name 3,IGNORE,ID 8,0.362588613,0.245743931,0.3609012
Name 3,IGNORE,ID 8,0.997325869,0.52338963,0.864007116
[download]

I need to loop through this file and calculate the mean and standard deviation for each Name and ID pair (cols 1 and 3). So as to produce an output like this:

Col1,Col3,mean ,standard Dev
Name 1,ID 1,VALUE ?,VALUE ?
Name 1,ID 2,VALUE ?,VALUE ?
Name 1,ID 3,VALUE ?,VALUE ?
Name 2,ID 1,VALUE ?,VALUE ?
Name 2,ID 2,VALUE ?,VALUE ?
Name 2,ID 3,VALUE ?,VALUE ?
Name 2,ID 4,VALUE ?,VALUE ?
Name 2,ID 5,VALUE ?,VALUE ?
Name 2,ID 6,VALUE ?,VALUE ?
Name 3,ID 1,VALUE ?,VALUE ?
Name 3,ID 2,VALUE ?,VALUE ?
Name 3,ID 3,VALUE ?,VALUE ?
Name 3,ID 4,VALUE ?,VALUE ?
Name 3,ID 5,VALUE ?,VALUE ?
Name 3,ID 6,VALUE ?,VALUE ?
Name 3,ID 7,VALUE ?,VALUE ?
Name 3,ID 8,VALUE ?,VALUE ?
[download]

Here is what l have so far:

#!/usr/bin/perl -w
# -------------------------------------------------
use strict;
use Getopt::Long;
use Pod::Usage;
use File::Spec;
Getopt::Long::Configure ("bundling");
# -------------------------------------------------
my $help = 0;
my $force = 0;
my $verbose = 0;
my $result = GetOptions(
    "help|h" =>\$help,
    "force|f"=>\$force, 
    "verbose|v"=>\$verbose,
#--------------------------------------------------
# Assign input data to an arrray
#---------------------------------------------------
scalar (@ARGV) == 1 or die pod2usage(1);
my $fname = $ARGV[0];
my $fnameout = $fname;
$fnameout =~ s/\.\w\w\w$/_conv.csv/;
# -------------------------------------------------
(-e $fname) or die "Unable to find input file: $fname\n";
(-e $fnameout and $force) and die "Output file already exisys. Use -f 
+to force: $fnameout\n";
my ($fin, $fout);
open ($fin, "<$fname") or die "Unable to open file: $fname\n";
open ($fout, ">$fnameout") or die "Unable to open output file: $fnameo
+ut\n";
my @headers = qw (Col_1 Col_3 Mean St_Dev);
print $fout (join (",", @headers),"\n");
# -------------------------------------------------
# Chomp all data
# -------------------------------------------------
my @data = <$fin>;
# -------------------------------------------------
my $cnt = 0;
foreach my $line (@data)
{
    $cnt ++;
    next unless $cnt > 1;                # Skip Header
    chomp($line);
    
}
[download]

I would really appreciate your help with this as my mind has got stuck on this loop. And l cant seem to work out whether to use an array or hash. Many thanks Monks!!

Comment on Mean and standard deviation loop Select or Download Code

Replies are listed 'Best First'.
Re: Mean and standard deviation loop by roboticus (Chancellor) on Jun 17, 2012 at 13:32 UTC
SixShot: When your input data is sorted, I normally approach it like this: # Compute average value for each group my ($prev_key, $cnt, $sum); foreach my $line (@data) { my ($key, $val) = parse_line($line); if (defined($prev_key) and $prev_key eq $key) { # Same group as last time, accumulate results ++$cnt, $sum += $val; } else { # New group starting. Print results from # previous group, then start new one. print "Group $prev_key avg=", $sum/$cnt, ", cnt=", $cnt, "\n"; $prev_key = $key, $cnt=1, $sum=$val; } } # Print results from last group. print "Group $prev_key avg=", $sum/$cnt, ", cnt=", $cnt, "\n"; [download] And when you're data isn't sorted, you can always sort it first! ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply] [d/l]
Re^2: Mean and standard deviation loop by SixShot (Novice) on Jun 17, 2012 at 13:42 UTC
Hi roboticus, Thanks for your help, can l ask what the parse_line subroutine is?	[reply]
Re^3: Mean and standard deviation loop by roboticus (Chancellor) on Jun 17, 2012 at 15:03 UTC
SixShot: Sure, it's just a routine to pull out the value(s) you're interested in. In your case, you could probably use split and adjust the variable names on the left to represent the value(s) you want. You can use 'undef' for the columns holding values you don't care about, or just give them names. I frequently do the latter for documentation (so I don't have to look up the file format to figure out what a particular column is in case I want to modify the program). ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply]
Re: Mean and standard deviation loop by morgon (Priest) on Jun 17, 2012 at 11:41 UTC
Just dumping all your data here may be an efficient way for you to get your problems solved by someone else, but it isn't for the community. At the very least you should make an attempt yourself. I am willing to discuss code, not someone else's data-dump.	[reply]
Re^2: Mean and standard deviation loop by SixShot (Novice) on Jun 17, 2012 at 11:58 UTC
,p>ahh apologies, l totally understand what you mean. Here is the start of my scripy #!/usr/bin/perl -w # ------------------------------------------------- use strict; use Getopt::Long; use Pod::Usage; use File::Spec; Getopt::Long::Configure ("bundling"); # ------------------------------------------------- my $help = 0; my $force = 0; my $verbose = 0; my $result = GetOptions( "help\|h" =>\$help, "force\|f"=>\$force, "verbose\|v"=>\$verbose, #-------------------------------------------------- # Assign input data to an arrray #--------------------------------------------------- scalar (@ARGV) == 1 or die pod2usage(1); my $fname = $ARGV[0]; my $fnameout = $fname; $fnameout =~ s/\.\w\w\w$/_conv.csv/; # ------------------------------------------------- (-e $fname) or die "Unable to find input file: $fname\n"; (-e $fnameout and $force) and die "Output file already exisys. Use -f +to force: $fnameout\n"; my ($fin, $fout); open ($fin, "<$fname") or die "Unable to open file: $fname\n"; open ($fout, ">$fnameout") or die "Unable to open output file: $fnameo +ut\n"; my @headers = qw (Col_1 Col_3 Mean St_Dev); print $fout (join (",", @headers),"\n"); # ------------------------------------------------- # Chomp all data # ------------------------------------------------- my @data = <$fin>; # ------------------------------------------------- my $cnt = 0; foreach my $line (@data) { $cnt ++; next unless $cnt > 1; # Skip Header chomp($line); } [download] its just the input section, l really am stuck on how to loop over this my programmers mind is still quite novice im afraid and l am still struggling on working through loops in my mind.	[reply] [d/l]
Re^3: Mean and standard deviation loop by morgon (Priest) on Jun 17, 2012 at 12:38 UTC
That is not an attempt to solve the problem at hand. It is just boiler-plate code (that you may simply have copied). Are you claiming you know how to read a file into an array but not how to loop in Perl? Your problem is to parse the data then partition the data and compute mean and std dev on the paritions. Before I provide any more feedback I would like to see an attempt there as otherwise I have the feeling you are simply trying to free-ride. This site is the Perl-monks, not the homework-monks.	[reply]
Re^4: Mean and standard deviation loop by SixShot (Novice) on Jun 17, 2012 at 13:23 UTC
Re^5: Mean and standard deviation loop by morgon (Priest) on Jun 17, 2012 at 13:48 UTC
Re^4: Mean and standard deviation loop by SixShot (Novice) on Jun 17, 2012 at 12:42 UTC
Re: Mean and standard deviation loop by Cristoforo (Curate) on Jun 17, 2012 at 15:51 UTC
This could also easily be solved using DBI to calculate the averages. If you are familiar with SQL, this could be a possible solution. #!/usr/bin/perl use strict; use warnings; use Text::Table; use DBI; my $dbh = DBI->connect("DBI:CSV:"); $dbh->{'csv_tables'}->{'data'} = { 'file' => 'junk.txt'}; my $sql = <<SQL; select Col1, Col3, AVG(Col4), AVG(Col5), AVG(Col6) from data group by Col1, Col3 order by Col1, Col3 SQL my $sth = $dbh->prepare( $sql ); $sth->execute; my $tb = Text::Table->new(qw/ Col1 Col3 Avg_Col4 Avg_Col5 Avg_Col6 /); while ( my $row = $sth->fetchrow_arrayref ) { $tb->load($row); } print $tb; __END__ C:\Old_Data\perlp>perl t.pl Col1 Col3 Avg_Col4 Avg_Col5 Avg_Col6 Name 1 ID 1 0.53750595725 0.66002015475 0.373256641 Name 1 ID 2 0.503016916125 0.6786437965 0.556675151625 Name 1 ID 3 0.36942296675 0.445537553 0.386080953375 Name 2 ID 1 0.516050550333333 0.3745506395 0.337977443166667 Name 2 ID 2 0.559323705444444 0.376110070666667 0.362031394222222 Name 2 ID 3 0.415733165 0.5957284203 0.4376514411 Name 2 ID 4 0.5109963958 0.492942305933333 0.669402401266667 Name 2 ID 5 0.547109591375 0.5205764764375 0.605138018875 Name 2 ID 6 0.5141908028 0.378785432866667 0.492416377133333 Name 3 ID 1 0.440476683375 0.600837193125 0.356844589375 Name 3 ID 2 0.503670895181818 0.558365503181818 0.471884158818182 Name 3 ID 3 0.460990542307692 0.487847332692308 0.347110462153846 Name 3 ID 4 0.502672743615385 0.629029938307692 0.652826947307692 Name 3 ID 5 0.485902119727273 0.350142792181818 0.519689121454545 Name 3 ID 6 0.554161077076923 0.544737969461538 0.565414750615385 Name 3 ID 7 0.564178885230769 0.604259375076923 0.369545730769231 Name 3 ID 8 0.5017849838 0.3991158152 0.515273186 [download] Chris	[reply] [d/l]
Re: Mean and standard deviation loop by cheekuperl (Monk) on Jun 17, 2012 at 12:57 UTC
I need to loop through this file and calculate the mean and standard deviation for each Name and ID pair (cols 1 and 3). `#Pseudocode/pseduoalgo - whatever you call it @arr=<FILE>; #slurp the file into array for $line (@arr) #Loop through the file { #Do you need to chomp the line? #Do you need to split the line on comma delimiter? #Do you need a mean calculation formula here? #Do you need a std dev formula here? #Do you need to print the calculated values in new file? }` [download]	[reply] [d/l]