just starting to learn loops and arrays. i understand how to call a single variable in an array ie:
$animals = gc "c:\temp\animals.txt"
foreach ($animal in $animals)
{write-host "The"$animal "sleeps tonight."}
what i'm trying to figure out is how to call two different variables from two different arrays...ie:
$animals = gc "c:\temp\animals.txt"
$colors = gc "c:\temp\colors.txt"
this is the part where I'm confused. how do I call a foreach loop to cycle though both files simultaneously?
desired output: The white lion sleeps tonight, The black panther sleeps tonight, etc...
One way is to use arry indexing. Assuming both files have same line count:
$animals = gc c:\temp\animals.txt
$colors = gc c:\temp\colors.txt
for($i=0; $i -lt $animals.length; $i++)
{
#print first line from animals
$animals[$i]
#print first line from colors
$colors[$i]
}
Assuming you have two text files (with same no. of entries) in C:\ you can write something like this -
$c = 0
$animal = Get-Content C:\Animal.txt
Get-Content C:\Color.txt | Foreach-Object{
Write-Host "The $_ $($animal[$c]) sleeps at night"
$c++
}
Related
I'm trying to read a gz file line by line in Perl6, however, I'm getting blocked:
How to read gz file line by line in Perl6 however, this method, reading everything into :out uses far too much RAM to be usable except on very small files.
I don't understand how to use Perl6's Compress::Zlib to get everything line by line, although I opened an issue on their github https://github.com/retupmoca/P6-Compress-Zlib/issues/17
I'm trying Perl5's Compress::Zlib to translate this code, which works perfectly in Perl5:
use Compress::Zlib;
my $file = "data.txt.gz";
my $gz = gzopen($file, "rb") or die "Error reading $file: $gzerrno";
while ($gz->gzreadline($_) > 0) {
# Process the line read in $_
}
die "Error reading $file: $gzerrno" if $gzerrno != Z_STREAM_END ;
$gz->gzclose() ;
to something like this using Inline::Perl5 in Perl6:
use Compress::Zlib:from<Perl5>;
my $file = 'chrMT.1.vcf.gz';
my $gz = Compress::Zlib::new(gzopen($file, 'r');
while ($gz.gzreadline($_) > 0) {
print $_;
}
$gz.gzclose();
but I can't see how to translate this :(
I'm confused by Lib::Archive example https://github.com/frithnanth/perl6-Archive-Libarchive/blob/master/examples/readfile.p6 I don't see how I can get something like item 3 here
There should be something like
for $file.IO.lines(gz) -> $line { or something like that in Perl6, if it exists, I can't find it.
How can I read a large file line by line without reading everything into RAM in Perl6?
Update Now tested, which revealed an error, now fixed.
Solution #2
use Compress::Zlib;
my $file = "data.txt.gz" ;
my $handle = try open $file or die "Error reading $file: $!" ;
my $zwrap = zwrap($handle, :gzip) ;
for $zwrap.lines {
.print
}
CATCH { default { die "Error reading $file: $_" } }
$handle.close ;
I've tested this with a small gzipped text file.
I don't know much about gzip etc. but figured this out based on:
Knowing P6;
Reading Compress::Zlib's README and choosing the zwrap routine;
Looking at the module's source code, in particular the signature of the zwrap routine our sub zwrap ($thing, :$zlib, :$deflate, :$gzip);
And trial and error, mainly to guess that I needed to pass the :gzip adverb.
Please comment on whether my code works for you. I'm guessing the main thing is whether it's fast enough for the large files you have.
A failed attempt at solution #5
With solution #2 working I would have expected to be able to write just:
use Compress::Zlib ;
.print for "data.txt.gz".&zwrap(:gzip).lines ;
But that fails with:
No such method 'eof' for invocant of type 'IO::Path'
This is presumably because this module was written before the reorganization of the IO classes.
That led me to #MattOates' IO::Handle like object with .lines ? issue. I note no response and I saw no related repo at https://github.com/MattOates?tab=repositories.
I am focusing on the Inline::Perl5 solution that you tried.
For the call to $gz.gzreadline($_): it seems like gzreadline tries to return the line read from the zip file by modifying its input argument $_ (treated as an output argument, but it is not a true Perl 5 reference variable[1]), but the modified value is not returned to the Perl 6 script.
Here is a possoble workaround:
Create a wrapper module in the curent directory, e.g. ./MyZlibWrapper.pm:
package MyZlibWrapper;
use strict;
use warnings;
use Compress::Zlib ();
use Exporter qw(import);
our #EXPORT = qw(gzopen);
our $VERSION = 0.01;
sub gzopen {
my ( $fn, $mode ) = #_;
my $gz = Compress::Zlib::gzopen( $fn, $mode );
my $self = {gz => $gz};
return bless $self, __PACKAGE__;
}
sub gzreadline {
my ( $self ) = #_;
my $line = "";
my $res = $self->{gz}->gzreadline($line);
return [$res, $line];
}
sub gzclose {
my ( $self ) = #_;
$self->{gz}->gzclose();
}
1;
Then use Inline::Perl5 on this wrapper module instead of Compress::Zlib. For example ./p.p6:
use v6;
use lib:from<Perl5> '.';
use MyZlibWrapper:from<Perl5>;
my $file = 'data.txt.gz';
my $mode = 'rb';
my $gz = gzopen($file, $mode);
loop {
my ($res, $line) = $gz.gzreadline();
last if $res == 0;
print $line;
}
$gz.gzclose();
[1]
In Perl 5 you can modify an input argument that is not a reference, and the change will be reflected in the caller. This is done by modifying entries in the special #_ array variable. For example: sub quote { $_[0] = "'$_[0]'" } $str = "Hello"; quote($str) will quote $str even if $str is not passed by reference.
I'm having an issue with the if then.
$result = getMachineInfo $rlprddeploy $mdt
"-MachineID- -LastContactAt- -LastIP- -Deployment Receiver Version-"
$machine = $result.MachineID
$result | % { '{0,-10} {1,23} {2,16} {3,20}' -f $_.MachineID, $_.LastContactAt, $_.LastIP, $_.DeploymentReceiverVersion }
#$result | ft -auto
if $_.DeploymentReceiverVersion is less than 5.46.54 then I'm going to send a file to do an update. If the version is 5.55 then nothing needs to be done.
I've been banging my head against this for a week now and I can't figure it out. Every $_.blahblah is information pulled from an SQL table on a server.
We've been sending out updates manually and I'd like to stop that.
PowerShell's If statement can be written just like any C like language:
if ($true) {Write-Host "True Yo" }
That said, you haven't posted exactly what your issues is, so this somewhat generic:
Creating a custom object:
$dep = New-Object psobject -Property #{DeploymentReceiverVersion = "5.000.11"; AppName = "OxenTails" }
Comparing this is going to pose a potential problem:
$dep.DeploymentReceiverVersion.GetType()
The version is a string, so the comparison is comparing strings:
$dep.DeploymentReceiverVersion -lt "5.000.12"
gives an expected result, but
$dep.DeploymentReceiverVersion -lt "5.000.101"
does not.
This however could work to compare each set of numbers:
$parts = $dep.DeploymentReceiverVersion.Split('.')
if ([int]$parts[0] -lt 6 -and [int]$parts[1] -lt 001 -and [int]$parts[2] -lt 101) {
#Do Stuff!
}
Additionally, as pointed out by #TheMadTechnician there is the System.Version type [Version]
It can be used with one of the overload methods:
[Version]::new(parts[0],parts[1], parts[2]) -lt [Version]::new(5,46,54)
Which is marginally more readable.
First time user, looking for help with a script that's been driving me crazy.
Basically, I need to create a set number of files of an exact size (512KB, 2MB, 1GB) to test a SAN. These files need to be filled with random text so that the SAN doesn't catch the nuls and does actually allocate the blocks - that's also the reason I couldn't just use fsutils.
Now, I've been messing with the new-bigrandomfile by Verboon and tweaking it to my needs.
However I'm getting the error:
You cannot call a method on a null-valued expression.
At L:\random5.ps1:34 char:9
+ $stream.Write($longstring)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
This is the bit of code I've come up with so far; I'll add a loop at the end to copy the file I just created N times so to fill up the lun.
Set-Strictmode -Version 2.0
#temp file
$file = "c:\temp\temp.rnd"
#charset size
$charset = 64
#Block Size
$blocksize = 512
#page size
$Pagesize = 512KB
#Number of blocks in a page
$blocknum = $Pagesize / $blocksize
#Resulting/desired test file size
$filesize = 1GB
#number of pages in a file
$pagenum = $filesize / $Pagesize
# create the stream writer
$stream = System.IO.StreamWriter $file
# get a 64 element Char[]; I added the - and _ to have 64 chars
[char[]]$chars = 'azertyuiopqsdfghjklmwxcvbnAZERTYUIOPQSDFGHJKLMWXCVBN0123456789-_'
1..$Pagenum | ForEach-Object {
# get a page's worth of blocks
1..$blocknum| ForEach-Object {
# randomize all chars and...
$rndChars = $chars | Get-Random -Count $chars.Count
# ...join them in a string
$string = -join $rndChars
# repeat random string N times to get a full block string length
$longstring = $string * ($blocksize / $charset)
# write 1 block to file
$stream.Write($longstring)
# release resources by clearing string variables
Clear-Variable string, longstring
}
}
$stream.Close()
$stream.Dispose()
# release resources through garbage collection
[GC]::Collect()
$file.Close()
I've tried a gazillion variants like:
$stream = [System.IO.StreamWriter] $file
$stream = System.IO.StreamWriter $file
$stream = NewObject System.IO.StreamWriter $file
Of course, being a total noob at powershell, I've tried using quotes, brackets, provided the full path instead of the variable, etc. All (or most) seem to be valid syntax variants, according to a ton of examples I found online, but the output is still the same.
In case you have any improvement to suggest or alternative way to perform this task I'm all ears.
Edited the script above: just a couple of " for $file made the error disappear, - thanks LinuxDisciple; however, the file gets created but stays at 0 bytes and the script stuck in a loop.
Fix your instantiation of StreamWriter to any of these correct variants:
$stream = [System.IO.StreamWriter]::new($file)
$stream = [IO.StreamWriter]::new($file) # the default namespace may be omitted
$stream = New-Object System.IO.StreamWriter $file
You can specify encoding:
$stream = [IO.StreamWriter]::new(
$file,
$false, # don't append
[Text.Encoding]::ASCII
)
See StreamWriter on MSDN for available constructors and parameters.
PowerShell ISE offers autocomplete with tooltips:
type [streamw and press Ctrl-Space to autocomplete the full .NET class name
type ]:: to see the available methods and properties
type new and press Ctrl-Space to see the constructor overrides
whenever needed, put the caret at the method name and press Ctrl-Space for the tooltip
I know nothing about powershell but a few things:
Are you sure $longstring has a value before you call stream.Write()? It sounds like it's null and that's why the error. If you can somehow output the value of $longstring to the console, it would help you make sure that it has a value.
Also, troubleshoot the code with a simplified version of your code, so that you can pinpoint what's going on, for example
$file = c:\temp\temp.rnd
$stream = System.IO.StreamWriter $file
$longstring = 'whatever'
$stream.Write($longstring)
I found a very old thread here that seemed to answer the question, but when I tried to implement the code I am not getting the expected variable expansion. Based on this
$Arguments = '$foo (Notepad.exe) bar'
$foo = 'Foooooo'
$InitSB = {$ExecutionContext.SessionState.Applications.Clear(); $ExecutionContext.SessionState.Scripts.Clear(); Get-Command | %{$_.Visibility = 'Private'}}
$SafeStringEvalSB = {param($str) $str}
$job = Start-Job -Init $InitSB -ScriptBlock $SafeStringEvalSB -ArgumentList $Arguments
Wait-Job $job > $null
Receive-Job $job
I would expect to get back Foooooo (Notepad.exe) bar
What have I got wrong here? And is there any difference between v2 and later versions?
I do have this working using $ExecutionContext.InvokeCommand.ExpandString(), but that allows for arbitrary code to execute as well, which I am trying to avoid. Ultimately I have a large number of different strings stored in XML, with different permutations of variables interspersed in the strings, and the actual values of those different variables are assigned at run time. And I need to push those values into the specific string of many possible wherever they occur. Because there are so many potential strings and variables I can't easily use a simple format approach. So ultimately I need the functionality of $ExecutionContext.InvokeCommand.ExpandString() but limited to actually just expanding variables, with no other code execution.
Any help greatly appreciated.
Alternatively you could just replace the text.
Param($var1,$var2,$var3)
$Content = Get-Content C:\Path\To\file.xml
$Content -replace '\$var1', "$var1" -replace '\$var2', "$var2" -replace '\$var3', "$var3"
As you have it written you won't get what you expect purely because you have single quotes around your string that you are assigning to $Arguments, meaning $foo wouldn't be treated as a variable anyway.
EDIT: Still won't work even with double quotes. Must assign value to $foo before referencing it in $Arguments.
$foo = 'Foooooo'
$Arguments = "$foo (Notepad.exe) bar"
$InitSB = {$ExecutionContext.SessionState.Applications.Clear(); $ExecutionContext.SessionState.Scripts.Clear(); Get-Command | %{$_.Visibility = 'Private'}}
$SafeStringEvalSB = {param($str) $str}
$job = Start-Job -Init $InitSB -ScriptBlock $SafeStringEvalSB -ArgumentList $Arguments
Wait-Job $job > $null
Receive-Job $job
I need to fill in a single PDF template multiple times and concat the results. When I say multiple, I mean up to a few hundred times, potentially over one thousand.
I can do this with pdftk fill_form, one by one, and then use pdftk cat. We can parallelize this fairly easily.
I'm curious if this is the only option, or if there is a piece of software (Linux + OSX, command line) that will allow me to say "take this template, and these sets of fields, fill out this form, and concat the files" so I can avoid doing every one individually. Then again, if something does exist, but it's not any faster than just doing the fork parallelization method, then it's probably not worth it.
My Perl library CAM::PDF can do this. The form filling is a bit weak (it doesn't support checkboxes, for example) but the concatenation works great.
#perl -w
use strict;
use CAM::PDF;
my $infile = 'in.pdf';
my $outfile = 'out.pdf';
my #fills = (
{ name => 'John' },
{ name => 'Fred' },
);
my $pdf = CAM::PDF->new($infile) or die $CAM::PDF::errstr;
for my $i (0 .. #fills-1) {
my $filledPDF = $i == 0 ? $pdf : CAM::PDF->new($infile);
$filledPDF->fillFormFields(%{$fills[$i]});
if ($i > 0) {
$pdf->appendPDF($filledPDF);
}
}
$pdf->cleanoutput($outfile) or die;