yesterday i asked this question and got many helpful replies, hoping the same will be true today. Here is my revised script.
#! /usr/bin/perl
use strict;
use warnings;
my $line;
my #array;
my $print;
open (OUT , ">","output.txt")or die "cant open: $!";
while ($line = <>){
chomp($line);
push(#array, $line);
if(#array == 250){
$print = print "[", join(",",#array), "]", "\n";
print OUT $print;
#array = []
}
}
Originally i simply stated that i need to print out the first 250 elements of an array to a text file, and that this array was built from standard input. What i didnt state is that the input, from which the array is built, may consist of several thousand lines. The reason for creating an array from this input is so that i can limit the size of the array to 250 entities, and then print the array as a formatted string. I then need to flush the array and resume building at what will become the 251st line of the input, and continue doing this process for the remainder of the input. Lets say the input is 5k lines, i want my output to be a text file containing the original 5k lines of input, but divided into strings made up of 250 array entities.
Currently the script is just printing the array to the screen and inside "ouput.txt" is a single line reading: 1111111.
$print = print "[", join(",",#array), "]", "\n";
print OUT $print;
Here you are assigning the return value of print to $print, which is 1, because the printing is successful. What you want to do is this:
print OUT "[", join(",",#array), "]", "\n";
Here's another option which just slightly modifies your script:
use strict;
use warnings;
my #array;
local $" = ',';
while (<>) {
chomp;
push #array, $_;
if ( #array == 250 ) {
print "[#array]\n";
undef #array;
}
}
Usage: perl script.pl Infile [>outFile]
The last, optional parameter directs output to a file.
The variable $" is holds Perl's list separator that's applied to an interpolated array, so join's not needed here.
Hope this helps!
#! /usr/bin/perl
use strict;
use warnings;
my $line;
my #array;
my $print;
open (OUT , ">","moloch_chunker_output.txt")or die "cant open: $!";
while ($line = <>){
chomp($line);
push(#array, $line);
if(#array == 250){
print OUT "[", join(",",#array), "]", "\n";
#array = ();
}
}
Thank you davs, that fixed it.
Related
I know this is a fairly simple question, but I cannot figure out how to store all of the values in my array the way I want to.
Here is a small portion what the .txt file looks like:
0 A R N D
A 2 -2 0 0
R -2 6 0 -1
N 0 0 2 2
D 0 -1 2 4
Each value is delimited by either two spaces - if the next value is positive - or a space and a '-' - if the next value is negative
Here is the code:
use strict;
use warnings;
open my $infile, '<', 'PAM250.txt' or die $!;
my $line;
my #array;
while($line = <$infile>)
{
$line =~ /^$/ and die "Blank line detected at $.\n";
$line =~ /^#/ and next; #skips the commented lines at the beginning
#array = $line;
print "#array"; #Prints the array after each line is read
};
print "\n\n#array"; #only prints the last line of the array ?
I understand that #array only holds the last line that was passed to it. Is there a way where I can get #array to hold all of the lines?
You are looking for push.
push #array, $line;
You undoubtedly want to precede this with chomp to snip any newlines, first.
If file is small as compared to available memory of your machine then you can simply use below method to read content of file in to an array
open my $infile, '<', 'PAM250.txt' or die $!;
my #array = <$infile>;
close $infile;
If you are going to read a very large file then it is better to read it line by line as you are doing but use PUSH to add each line at end of array.
push(#array,$line);
I will suggest you also read about some more array manipulating functions in perl
You're unclear to what you want to achieve.
Is every line an element of your array?
Is every line an array in your array and your "words" are the elements of this array?
Anyhow.
Here is how you can achieve both:
use strict;
use warnings;
use Data::Dumper;
# Read all lines into your array, after removing the \n
my #array= map { chomp; $_ } <>;
# show it
print Dumper \#array;
# Make each line an array so that you have an array of arrays
$_= [ split ] foreach #array;
# show it
print Dumper \#array;
try this...
sub room
{
my $result = "";
open(FILE, <$_[0]);
while (<FILE>) { $return .= $_; }
close(FILE);
return $result;
}
so you have a basic functionality without great words. the suggest before contains the risk to fail on large files. fastest safe way is that. call it as you like...
my #array = &room('/etc/passwd');
print room('/etc/passwd');
you can shorten, rename as your convinience believes.
to the kidding ducks nearby: by this way the the push was replaced by simplictiy. a text-file contains linebreaks. the traditional push removes the linebreak and pushing up just the line. the construction of an array is a simple string with linebreaks. now contain the steplength...
Here, I want to print the data in each line as 3 separate values with ":" as separator. The file BatmanFile.txt has the following details:
Bruce:Batman:bat#bat.com
Santosh:Bhaskar:santosh#santosh.com
And the output I expected was:
Bruce
Batman
bat#bat.com
Santosh
Bhaskar
santosh#santosh.com
The output after executing the script was:
Bruce
Batman
bat#bat.com
Bruce
Batman
bat#bat.com
Please explain me what I am missing here:
use strict;
use warnings;
my $file = 'BatmanFile.txt';
open my $info, $file or die "Could not open $file: $!";
my #resultarray;
while( my $line = <$info>) {
#print $line;
chomp $line;
my #linearray = split(":", $line);
push(#resultarray, #linearray);
print join("\n",$resultarray[0]),"\n";
print join("\n",$resultarray[1]),"\n";
print join("\n",$resultarray[2]),"\n";
}
close $info;
You are looping through file line by line. You have stored all lines (after splitting) in an array. Once the loop finishes you have all data in resultarray array, just print whole array after the loop (instead of printing just first 3 indexes which are you doing at the moment).
#!/usr/bin/perl
use strict;
use warnings;
my #resultarray;
while( my $line = <DATA>){
chomp $line;
my #linearray = split(":", $line);
push #resultarray, #linearray;
}
print "$_\n" foreach #resultarray;
__DATA__
Bruce:Batman:bat#bat.com
Santosh:Bhaskar:santosh#santosh.com
Demo
You can avoid all variables and do something like below
while(<DATA>){
chomp;
print "$_\n" foreach split(":");
}
One liner:
perl -e 'while(<>){chomp; push #result, split(":",$_);} print "$_\n" foreach #result' testdata.txt
When you do:
push(#resultarray, #linearray);
you're pushing #linearray into #resultarray at the end, so index 0 through 2 is still the items from the first time you pushed #linearray.
To overwrite #resultarray with the values from the second iteration, do:
#resultarray = #linearray;
instead.
Alternatively, use unshift to place #linearray at the start of #resultarray, as suggested by Sobrique:
unshift #resultarray, #linearray;
So, you just want to transliterate : to \n?
$ perl -pe 'tr/:/\n/' data.txt
Output:
Bruce
Batman
bat#bat.com
Santosh
Bhaskar
santosh#santosh.com
use strict;
use warnings;
my $file = 'BatmanFile.txt';
open my $info, $file or die "Could not open $file: $!";
my #resultarray;
while( my $line = <$info>) {
#print $line;
chomp $line;
my #linearray = split(":", $line);
#push(#resultarray, #linearray);
print join("\n",$linearray[0]),"\n";
print join("\n",$linearray[1]),"\n";
print join("\n",$linearray[2]),"\n";
}
close $info;
Was working on this script when I came across a weird anomaly. When I go to print #extract after declaring it, it prints correctly the following:
------MMMMMMMMMMMMMMMMMMMMMMMMMM-M-MMMMMMMM
------SSSSSSSSSSSSSSSSSSSSSSSSSS-S-SSSSSDTA
------TIIIIIIIIIIIIITIIIVVIIIIII-I-IIIIITTT
Now the weird part, when I then try to print or return #extract (or $column) inside of the while loop, it comes up empty, thus rendering the rest of the script useless. I've never come across this before up until now, haven't been able to find any documentation or people with similar problems as mine. Below is the code, I marked with #<------ where the problems are and are not, to see if anyone can have any idea what is going on? Thank you kindly.
P.S. I am utilizing perl version 5.12.2
use strict;
use warnings;
#use diagnostics;
#use feature qw(say);
open (S, "Val nuc align.txt") || die "cannot open FASTA file to read: $!";
open (OUTPUT, ">output.txt");
my #extract;
my $sum = 0;
my #lines = <S>;
my #seq = ();
my $start = 0; #amino acid column start
my $end = 10; #amino acid column end
#Removing of the sequence tag until amino acid sequence composition (from >gi to )).
foreach my $line (#lines) {
$line =~ s/\n//g;
if ($line =~ />/g) {
$line =~ s/>.*\]/>/g;
push #seq, $line;
}
else {
push #seq, $line;
}
}
my $seq = join ('', #seq);
my #seq_prot = join "\n", split '>', $seq;
#seq_prot = grep {/[A-Z]/} #seq_prot;
#number of sequences
print OUTPUT "Number of sequences:", scalar (grep {defined} #seq_prot), "\n";
#selection of amino acid sequence. From $start to $end.
my #vertical_array;
while ( my $line = <#seq_prot> ) {
chomp $line;
my #split_line = split //, $line;
for my $index ( $start..$end ) { #AA position, extracts whole columns
$vertical_array[$index] .= $split_line[$index];
}
}
# Print out your vertical lines
for my $line ( #vertical_array ) {
my $extract = say OUTPUT for unpack "(a200)*", $line; #split at end of each column
#extract = grep {defined} $extract;
}
print OUTPUT #extract; #<--------------- This prints correctly the input
#Count selected amino acids excluding '-'.
my %counter;
while (my $column = #extract) {
print #extract; #<------------------------ Empty print, no input found
}
Update: Found the main problem to be with the unpack command, I thought I could utilize it to split my columns of my input at X elements (43 in this case). While this works, the minute I change $start to another number that is not 0 (say 200), the code brings up errors. Probably has something to do with the number of column elements does not match the lines. Will keep updated.
Write your last while loop the same way as your previous for loop. The assignment
my $column = #extract
is in scalar context, which does not give you the same result as:
for my $column (#extract)
Instead, it will give you the number of elements in the array. Try this second option and it should work.
However, I still have a concern, because in fact, if #extract had anything in it, you would obtain an infinite loop. Is there any code that you did not include between your two commented lines?
I'm trying to simply pop off each numeric value and add them together to gain a total.
Input file:
Samsung 46
RIM 16
Apple 87
Microsoft 30
My code compiles, however, it only returns 0:
open (UNITS, 'units.txt') || die "Can't open it $!";
my #lines = <UNITS>;
my $total = 0;
while (<UNITS>) {
chomp;
my $line = pop #lines;
$line += $total;
}
print $total;
No need to slurp all lines into an array if you're just going to loop through them anyway with a while. Also, you need to split each line to get your numbers.
use warnings;
use strict;
open (UNITS, 'units.txt') || die "Can't open it $!";
my $total = 0;
while (<UNITS>) {
chomp;
my $num = (split)[1];
$total += $num;
}
print "$total\n";
__END__
179
There are three problems here
You are trying to add strings like 'Samsung 46' + 'RIM 16'
You read the entire file into #lines and then try to read more from the file in the while loop. That loop is never entered because you have already read to end of file
You are adding $total to the (undeclared) variable $line within the loop, instead of the other way around. So $total remains at zero and $line keeps having zero added to it
It is best to use while to read files unless you need something other than sequential access to the records, so removing #lines is a start.
It isn't completely clear which part of the records you want to accumulate. This program splits the lines on whitespace and adds together the last field of each line.
You must always use strict and use warnings at the start of every program. It is a measure that will make it far easier to locate bugs in your code. It is also best to use lexical file handles rather than the global one you used, and the three-parameter form of open.
use strict;
use warnings;
open my $units, '<', 'units.txt' or die "Can't open it: $!";
my $total;
while (<$units>) {
my #fields = split;
$total += $fields[-1];
}
print $total;
output
179
use strict;
use warnings;
open my $fh, "<", "units.txt" or die "well...";
my $total = 0;
while(<$fh>){
chomp;
my ($string, $num) = split(" ", $_);
$total += $num;
}
print $total;
This problem is a doddle with a one-liner:
$ perl -ane '$sum += $F[1] }{ print $sum' units.txt
Explanation
-a enables autosplit, each line is split and stored in #F
-n loops over the file line by line
-e tells perl that the next argument is to be treated as Perl code
the LHS of the Eskimo-kiss (that funny-looking }{ in the middle) is performed for every line in the input file, RHS performed only once
LHS accumulates the second column of every line in $sum
RHS prints the result of $sum once all lines have been processed
dear my fellow perl masters in the world~!
I need your help.
I have a string file A and a number file B like this:
File A:
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
...and so on till 200.
File B:
3, 6, 2, 5, 6, 1, ... 2
(total 200 numbers in an array)
then, with the numbers in file B, I would like to cut each string from the start position to the number of characters in File B.
E.g. as File B starts with 3, 6, 2 ...
File A will be
AAAAAAAAAAAAAAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
like this.
So. this is my code so far...
use strict;
if (#ARGV != 2) {
print "Invalid usage\n";
print "Usahe: perl program.pl [num_list] [string_file]\n";
exit(0);
}
my $numbers=$ARGV[0];
my $strings=$ARGV[1];
my $i;
open(LIST,$number);
open(DATA,$strings);
my #list = <LIST>;
my $list_size = scalar #sp_list;
for ($i=0;$i<=$list_size;$i++) {
print $i,"\n";
#while (my $line = <DATA>) {
}
close(LIST);
close(DATA);
As the strings and numbers are 200 I changed the array into a scalar value to work on every numbers of every strings.
I'm working on this. and I know I suppose to use a pos function but i do not know how to match each number with each string. is reading the string first by while? or using for to know how many time that I have to run this to achieve the result?
Your help will be much appreciated!
Thank you.
I will be working on it, too. Need your feedback.
It is good that you use strict, and you should also use warnings. Further things to note:
You should check the return value of open to make sure they did not fail. You should also use the three argument form of open and use a lexical file handle. Especially when handling command line arguments, which does pose a security risk.
open my $listfh, "<", $file or die $!;
You may wish to use a safety precaution
use ARGV::readonly;
You can easily make the list of numbers with a map statement. Assuming the numbers are in a comma separated list:
my #list = map split(/\s*,\s*/), <$listfh>;
This will split the input line(s) on comma and strip excess whitespace.
When reading your input file, you do not need to use a counter variable. You can simply do
open my $inputfh, "<", $file or die $!;
while (<$inputfh>) {
my $length = shift #list; # these are your numbers
chomp; # remove newline
my $string = substr($_, 0, -$length); # negative length on substr
print "$string\n";
}
The negative length on substr makes it leave that many characters off the end of the string.
Here is a one-liner in action that demonstrates these principles:
perl -lwe '$f = pop; # save file name for later
#nums = map split(/\s*,\s*/), <>; # process first file
push #ARGV, $f; # put back file name
while (<>) {
my $len = shift #nums;
chomp;
print substr($_,0,-$len);
}' fileb.txt filea.txt
Output:
AAAAAAAAAAAAAAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
DDDDDDDDDDDDDDDDDDDDDDDDDDD
EEEEEEEEEEEEEEEEEEEEEEEEEE
Note the use of implicit open of file name arguments by manipulating #ARGV. Also handling newlines with -l switch.
Here is my suggestion. It does use autodie so that there is no need to explicitly check the status of open calls, and temporarily undefines $/ - the input record separator - so that all of the num_list file is read in one go. You aren't clear whether this file will always contain just single line, in which case you can omit local $/.
The numbers are extracted from the text using a regular expression /\d+/g returns all the strings of digits in the input as a list.
The second parameter to substr is the start position of the substring you want, and using a negative number counts from the end of the string instead of the beginning. The third parameter is the number of characters in the substring, and the fourth is a string to replace that substring in the target variable. So substr $data, -$n, $n, '' replaces the substring of length $n starting $n characters from the end with an empty string - i.e. it deletes it.
Note that if it is your intention to remove the given number of characters from the beginning of the string, then you would write substr $data, 0, $n, '' instead.
use strict;
use warnings;
use autodie;
unless (#ARGV == 2) {
print "Usage: perl program.pl [num_list] [string_file]\n";
exit;
}
my #numbers;
{
open my $listfh, '<', $ARGV[0];
local $/;
my $numbers = <$listfh>;
#numbers = $numbers =~ /\d+/g;
};
open my $datafh, '<', $ARGV[1];
for my $i (0 .. $#numbers) {
print "$i\n";
my $n = $numbers[$i];
my $data = <$datafh>;
chomp $data;
substr $data, -$n, $n, '';
print "$data\n";
}
Here is how I would do it. substr is the function to remove a part of a string. From your example, it is not clear whether you want to remove the characters at the beginning or at the end. Both alternatives are shown here:
#!/usr/bin/perl
use warnings;
use strict;
if (#ARGV != 2) {
die "Invalid usage\n"
. "Usage: perl program.pl [num_list] [string_file]\n";
}
my ($number_f, $string_f) = #ARGV;
open my $LIST, '<', $number_f or die "Cannot open $number_f: $!";
my #numbers = split /, */, <$LIST>;
close $LIST;
open my $DATA, '<', $string_f or die "Cannot open $string_f: $!";
while (my $string = <$DATA>) {
substr $string, 0, shift #numbers, q(); # Replace the first n characters with an empty string.
# To remove the trailing portion, replace the previous line with the following:
# my $n = shift #numbers;
# substr $string, -$n-1, $n, q();
print $string;
}
You were not checking the return value of open. Try to remember to always do that.
Do not declare variables far before you are going to use them ($i here).
Do not use C-style for loops if you do not have to. They are prone to fence post errors.
You can use substr():
use strict;
use warnings;
if (#ARGV != 2) {
print "Invalid usage\n";
print "Usage: perl program.pl [num_list] [string_file]\n";
exit(0);
}
my $numbers=$ARGV[0];
my $strings=$ARGV[1];
open my $list, '<', $numbers or die "Can't open $numbers: $!";
open my $data, '<', $strings or die "Can't open $strings: $!";
chomp(my $numlist = <$list>);
my #numbers = split /\s*,\s*/,$numlist;
for my $chop_length (#numbers)
{
my $data = <$data> // die "not enough data in $strings";
print substr($data,0,length($data)-$chop_length)."\n";
}
Your specs say you want "... to cut each string from the start position to the number of characters in File B." I agree with choroba that it's not perfectly clear whether characters from the start or the end of the string are to be cut. However, I tend to think that you want to remove characters from the beginning when you say, "... from the start position ...", but a string like ABCDEFGHIJKLMNOPQRSTUVWXYZ012345 would help clarify this issue.
This option is not as well self-documenting as the other solutions, but a discussion of it will follow:
use strict;
use warnings;
#ARGV == 2 or die "Usage: perl program.pl [num_list] [string_file]\n";
open my $fh, '<', pop or die "Cannot open string file: $!";
chomp( my #str = <$fh> );
local $/ = ', ';
while (<>) {
chomp;
print +( substr $str[ $. - 1 ], $_ ) . "\n";
}
Strings:
ABCDEFGHIJKLMNOPQRSTUVWXYZ012345
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
Numbers:
3, 6, 2, 5, 6
Output:
DEFGHIJKLMNOPQRSTUVWXYZ012345
BBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
DDDDDDDDDDDDDDDDDDDDDDDDDDD
EEEEEEEEEEEEEEEEEEEEEEEEEE
The strings' file name is poped off #ARGV (since an explicit argument for pop is not used) and passed to open to read the strings into #str. The record separator is set to ', ' so chomp leaves only the number. The current line number in $. is used as part of the index to the corresponding #str element, and the remaining characters in the string from n on are printed.