Perl printing array values getting weird - arrays

I am experiencing something that i don't understand here's my code :
#iprouteur = split( /./, $arraylist[1] );
print "lip du routeur est $arraylist[1]\n";
for ( $i = 2; $i <= $#arraylist; $i++ ) {
print "we found secondary which is $arraylist[$i]\n";
#secondary = split( /./, $arraylist[$i] );
print "voici les ip a comparer : $iprouteur[0] $iprouteur[1] $iprouteur[2] et $secondary[0] $secondary[1] $secondary[2] \n";
if ( $iprouteur[0] eq $secondary[0] && $iprouteur[1] eq $secondary[1] && $iprouteur[2] eq $secondary[2] ) {
print "we need to splice \n";
}
}
The output is like :
lip du routeur est 126.x.x.x
we found secondary which is 126.x.x.x/24
voici les ip a comparer : et
we need to splice
Why perl can't find what is inside the $iprouteur[x] and $secondary[y] variable ?

The problem is that you split with the regex /./. The period . is a meta character, and it is the wildcard, matching any char except newline. So it consumes your entire string when used, and returns a bunch of empty strings. The solution is to escape the period:
#secondary = split(/\./, $arraylist[$i]);
# ^--- note the backslash
Also what I meant in the comments is that this line:
print "voici les ip a comparer : $iprouteur[0] $iprouteur[1] $iprouteur[2] et $secondary[0] $secondary[1] $secondary[2] \n";
can be written:
print "voici les ip a comparer : #iprouteur[0,1,2] et #secondary[0,1,2] \n";
Which is easier both to read and to write.

My bad, i forgot to use "." with the split function
I forgot that it was a special char.
#iprouteur = split(/\./,$arraylist[1]);
#secondary = split(/\./, $arraylist[$i]);

Related

loop through elements of array to find character perl

I have a perl array where I only want to loop through elements 2-8.
The elements are only meant to contain numbers, so if any of those elements contain a letter, I want to set an error flag = 1, as well as some other variables as seen.
The reason I have 2 error flag variables is due to scope rules within the loop.
fields is an array, I created by splitting another irrelevant array by the " " key.
So, when I try to print error_line2, error_fname2 from outside the loop, I get this:
Use of uninitialized value $error_flag2 in numeric eq (==)
I don't know why, because I've initialized the value within the loop and created the variable outside the loop.
Not sure if I'm even looping to find characters correctly, so then it's not setting the error_flag2 = 1.
Example line:
bob hankerman 2039 3232 23 232 645 64x3 324
since element 7 has the letter 'x' , I want the flag to be set to 1.
#!/usr/bin/perl
use strict;
use warnings;
use Scalar::Util qw(looks_like_number);
my $players_file = $ARGV[0];
my #players_array;
open (my $file, "<", "$players_file")
or die "Failed to open file: $!\n";
while(<$file>) {
chomp;
push #players_array, $_;
}
close $file;
#print join "\n", #players_array;
my $num_of_players = #players_array;
my $error_flag;
my $error_line;
my $error_fname;
my $error_lname;
my $error_flag2=1;
my $error_line2;
my $error_fname2;
my $error_lname2;
my $i;
foreach my $player(#players_array){
my #fields = split " ", $player;
my $size2 = #fields;
for($i=2; $i<9; $i++){
print "$fields[$i] \n";
if (grep $_ =~ /^[a-zA-Z]+$/){
my $errorflag2 = 1;
$error_flag2 = $errorflag2;
my $errorline2 = $player +1;
$error_line2 = $errorline2;
my $errorfname2 = $fields[0];
$error_fname2 = $errorfname2;
}
}
if ($size2 == "9" ) {
my $firstname = $fields[0];
my $lastname = $fields[1];
my $batting_average = ($fields[4]+$fields[5]+$fields[6]+$fields[7]) / $fields[3];
my $slugging = ($fields[4]+($fields[5]*2)+($fields[6]*3)+($fields[7]*4)) / $fields[3];
my $on_base_percent = ($fields[4]+$fields[5]+$fields[6]+$fields[7] +$fields[8]) / $fields[2];
print "$firstname ";
print "$lastname ";
print "$batting_average ";
print "$slugging ";
print "$on_base_percent\n ";
}
else {
my $errorflag = 1;
$error_flag = $errorflag;
my $errorline = $player +1;
$error_line = $errorline;
my $errorfname = $fields[0];
$error_fname = $errorfname;
my $errorlname = $fields[1];
$error_lname = $errorlname;
}
}
if ($error_flag == "1"){
print "\n Line $error_line : ";
print "$error_fname, ";
print "$error_lname :";
print "Line contains not enough data.\n";
}
if ($error_flag2 == "1"){
print "\n Line $error_line2 : ";
print "$error_fname2, ";
print "Line contains bad data.\n";
}
OK, so the problem you've got here is that you're thinking of grep in Unix terms - a text based thing. It doesn't work like that in perl - it operates on a list.
Fortunately, this is pretty easy to handle in your case, because you can split your line into words.
Without your source data, this is hopefully a proof of concept:
#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
while ( <DATA> ) {
#split the current line on whitespace into an array.
#first two elements get assigned to firstname lastname, and then the rest
#goes into #values
my ( $firstname, $lastname, #values ) = split; #works on $_ implicitly.
#check every element in #values, and test the regex 'non-digit' against it.
my #errors = grep { /\D/ } #values;
#output any matches e.g. things that contained 'non-digits' anywhere.
print Dumper \#errors;
#an array in a scalar context evaluates as the number of elements.
#we need to use "scalar" here because print accepts list arguments.
print "There were ", scalar #errors, " errors\n";
}
__DATA__
bob hankerman 2039 3232 23 232 645 64x3 324
Or reducing down the logic:
#!/usr/bin/perl
use strict;
use warnings;
while ( <DATA> ) {
#note - we don't need to explicity specify 'scalar' here,
#because assigning it to a scalar does that automatically.
#(split) splits the current line, and [2..8] skips the first two.
my $count_of_errors = grep { /\D/ } (split)[2..8];
print $count_of_errors;
}
__DATA__
bob hankerman 2039 3232 23 232 645 64x3 324
First : You don't need to use "GREP", Simply you can match the string with "=~" in perl and you can print matched value with $&.
Second : You should use $_ if and only if there is not other variable used in the loop. There is already $i used in the loop, you can write the loop as :
for my $i (2..9) {
print "$i\n";
}
or
foreach(2..9) {
print "$_\n";
}

Perl matching multidimensional array elements

Im not getting any output, anyone get where the issue lies,
matching or calling?
(The two subarrays in the multidimensional array have the same length.)
//Multidimensional array,
//Idarray = Fasta ID, Seqarray = "ATTGTTGGT" sequences
#ordarray = (\#idarray, \#seqarray);
//This calling works
print $ordarray[0][0] , "\n";
print $ordarray[1][0] , "\n", "\n";
// Ordarray output = "TTGTGGCACATAATTTGTTTAATCCAGAT....."
User inputs a search string, loop iterates the sequence dimension,
and counts amount of matches. Prints number of matches and the corresponding ID from the ID dimension.
//The user input-searchstring
$sestri = <>;
for($r=0;$r<#idarray;$r++) {
if ($sestri =~ $ordarray[1][$r] ){
print $ordarray[0][$r] , "\n";
$counts = () = $ordarray[0][$r] =~ /$sestri/g;
print "number of counts: ", $counts ;
}
I think the problem lies with this:
$sestri = <>;
That may well not be doing what you intended - your comment says "user specified search string" but that's not what that operator does.
What it does, is open the filename you specifed on the command line, and 'return' the first line.
I would suggest that if you want to grab a search string from command line you want to do it via #ARGV
E.g.
my ( $sestri ) = #ARGV; # will give first word.
However, please please please switch on use strict and use warnings. You should always do this prior to posting on a forum for assistance.
I would also question quite why you need a two dimensional array with two elements in it though. It seems unnecessary.
Why not instead make a hash, and key your "fasta ids" to the sequence?
E.g.
my %id_of;
#id_of{#seqarray} = #idarray;
my %seq_of;
#seq_of{#id_array} = #seqarray;
I think this would suit your code a bit better, because then you don't have to worry about the array indicies at all.
use strict;
use warnings;
my ($sestri) = #ARGV;
my %id_of;
#id_of{#seqarray} = #idarray;
foreach my $sequence ( keys %id_of ) {
##NB - this is a pattern match, and will be 'true'
## if $sestri is a substring of $sequence
if ( $sequence =~ m/$sestri/ ) {
print $id_of{$sequence}, "\n";
my $count = () = $sequence =~ m/$sestri/g;
print "number of counts: ", $count, "\n";
}
}
I've rewritten it a bit, because I'm not entirely understanding what your code is doing. It looks like it's substring matching in #seqarray but then returning the count of matching elements in #idarray I don't think that makes sense, but if it does, then amend according to your needs.

Comparing two strings line by line in Perl

I am looking for code in Perl similar to
my #lines1 = split /\n/, $str1;
my #lines2 = split /\n/, $str2;
for (int $i=0; $i<lines1.length; $i++)
{
if (lines1[$i] ~= lines2[$i])
print "difference in line $i \n";
}
To compare two strings line by line and show the lines at which there is any difference.
I know what I have written is mixture of C/Perl/Pseudo-code. How do I write it in the way that it works on Perl?
What you have written is sort of ok, except you cannot use that notation in Perl lines1.length, int $i, and ~= is not an operator, you mean =~, but that is the wrong tool here. Also if must have a block { } after it.
What you want is simply $i < #lines1 to get the array size, my $i to declare a lexical variable, and eq for string comparison. Along with if ( ... ) { ... }.
Technically you can use the binding operator to perform a string comparison, for example:
"foo" =~ "foobar"
But it is not a good idea when comparing literal strings, because you can get partial matches, and you need to escape meta characters. Therefore it is easier to just use eq.
Using C-style for loops is valid, but the more Perl-ish way is to use this notation:
for my $i (0 .. $#lines1)
Which will iterate over the range 0 to the max index of the array.
Perl allows you to open filehandles on strings by using a reference to the scalar variable that holds the string:
open my $string1_fh, '<', \$string1 or die '...';
open my $string2_fh, '<', \$string2 or die '...';
while( my $line1 = <$string1_fh> ) {
my $line2 = <$string2_fh>;
....
}
But, depending on what you mean by difference (does that include insertion or deletion of lines?), you might want something different.
There are several modules on CPAN that you can inspect for ideas, such as Test::LongString or Algorithm::Diff.
my #lines1 = split(/^/, $str1);
my #lines2 = split(/^/, $str2);
# splits at start of line
# use /\n/ if you want to ignore newline and trailing spaces
for ($i=0; $i < #lines1; $i++) {
print "difference in line $i \n" if (lines1[$i] ne lines2[$i]);
}
Comparing Arrays is a way easier if you create a Hashmap out of it...
#Searching the difference
#isect = ();
#diff = ();
%count = ();
foreach $item ( #array1, #array2 ) { $count{$item}++; }
foreach $item ( keys %count ) {
if ( $count{$item} == 2 ) {
push #isect, $item;
}
else {
push #diff, $item;
}
}
#Output
print "Different= #diff\n\n";
print "\nA Array = #array1\n";
print "\nB Array = #array2\n";
print "\nIntersect Array = #isect\n";
Even after spliting you could compare them as Array.

Reversing each scalar of an array in Perl

How do you reverse each string in an array of say three strings without reversing the order of the strings within the array?
Here is my program and the last command is where I try to take each element of the array and reverse it. For example: if I put it Andy Sam as input I want to get back ydnA maS, not maS ydnA. What am I doing wrong?
I thought that if I put the input into array #ref and took each element of that array via a foreach loop and reversed each element that it should turn out right.
print "Please enter your name: \n";
$userinput = <STDIN>;
chomp ($userinput);
#ref = $userinput;
print "Hello, $userinput.\n";
#get_characters = split(/ /, $userinput);
$strin = join ("" , #get_characters);
$m = length $strin;
print "Your name has ", "$m" , " characters in it.\n";
foreach $e(#ref)
{
$e = reverse $e;
print $e;
}
Your problem is that the array that you're iterating on has only one element. You need to split the name to get individual words:
my #ref = $userinput; # <-- contains a single string.
my #words = split ' ', $userinput;
Then juse use map. The only trick is that you have to force a scalar context.
my #words = qw(Andy Sam);
#words = map {scalar reverse} #words;
print "#words";
Outputs:
ydnA maS
Could also use a for loop to edit the same array:
$_ = reverse for #words;

tcl exec with file in parameter doesn't work

I'm working on a file explorer inTCL/Tk and I want to add a little thing to execute commands with the current selection (using %l %f) %l executing with the full list and %f executing the commmand with each file.
my only problem is that if I type a command like "gedit" for eg it works but as soon as I type a command with argument it doesn't work ...
I've been looking everywhere and I don't get it...
If someone could help me...
btw getl var Name is a function that returns me a FileName in full path (/home/...) and if I return the string that is supposed to be executed and put it in a terminal it works...
Here is the code:
proc tl_exec {liste command } {
#lorsqu'il faut effectué la commande avec la liste en param
if { [string first "%l" $command] > 0} {
foreach v $liste {
lappend args [getl $v Name]
}
set com [string map [list "%l" [join $args " "] ] $command ]
puts $com
set val [exec [split $com " "] ]
} elseif { [string first "%f" $command] > 0} {
#lorsqu'il faut effectué la commande pour chaque fichier
foreach v $liste {
set com [string map list ["%f" [getl $v "Name"] ] $command ]
lappend val [ exec [split $com " "] ]
}
} else {
#lorsqu'on a pas de fichiers
set val [exec $command]
}
}
Thanks a lot
Your code has more than a single problem, it will probably break with special chars or spaces in filenames too, as you do not quoting at all.
But you are right about exec considering everything as a single command.
set val [exec [split $com " "] ]
does not do what you expect, split returns a list, but does not automagically turn that list into extra args for exec.
If you use Tcl 8.5 you can try:
set val [exec {*}[split $com " "] ]
which turns the list into single arguments to pass to exec.
But the code you use is brittle in general, as you do not handle any exit codes or programs writing to stderr, so a more elaborate solution would be needed to be robust.
Have a look at http://wiki.tcl.tk/1039 especially the discussions on the bottom of the page.

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