How to get maximum value of a text file using (foreach) loop?

Question

The text file is numbers.txt:

1;2;5;6;1;3
9;6;16;9;2
6;23;3
3;8;9

My code is:

$a = Get-Content .\numbers.txt
$maximum = 0
foreach ($i in $a) {
    if ([int]$i.Split(";") -gt $maximum) {
        $maximum = $i.Split(";")
    }
}
$maximum

I know, there is something wrong with the types (string-integer), but I don't know how to fix it.

PS: If I do it this way, it works, but it's a time-consuming solution to find the max value for every column separately:

$a = Get-Content .\numbers.txt
$maximum = 0
foreach ($i in $a) {
    if ([int]$i.Split(";")[0] -gt $maximum) {
        $maximum = $i.Split(";")[0]
    }
}
$maximum

Maximum value for each row or for the whole content?

Reza Aghaei
– Reza Aghaei

2017-12-13 06:20:11 +00:00
Commented Dec 13, 2017 at 6:20 — Reza Aghaei
– Reza Aghaei, Commented Dec 13, 2017 at 6:20

TessellatingHeckler · Accepted Answer · 2017-12-13 08:01:19Z

3

I know, there is something wrong with the types (string-integer), but I don't know how to fix it

What's wrong is that $a is the lines in the file and $i is a line and you need to split that separately into numbers:

$a = get-content .\numbers.txt
$maximum = 0
foreach ( $line in $a )
{
    foreach ( $i in $line.Split(';') )
    {
        if ( [int]$i -gt $maximum )
        {
            $maximum = [int]$i
        }
    }
}
$maximum

But also what's wrong is that you're writing (Java/C#/Python/C/otherlang) in PowerShell, this is not good PowerShell habits.

Get-Content .\numbers.txt | 
    ForEach-Object { $_.Split(';') } | 
    Measure-Object -Maximum |
    Select-Object -ExpandProperty Maximum

Or if you want it short and type-able:

gc .\numbers.txt | foreach split ';' | measure -max

edited Dec 13, 2017 at 8:01

answered Dec 13, 2017 at 7:54

TessellatingHeckler

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Comments

Bacon Bits · Accepted Answer · 2017-12-13 05:36:38Z

1

For the whole file:

Get-Content -Path .\Numbers.txt | 
    ForEach-Object {
        $_.Split(';')
    } | ForEach-Object {
        [int]$_
    } | Measure-Object -Maximum |
    Select-Object -ExpandProperty Maximum

answered Dec 13, 2017 at 5:36

Bacon Bits

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9 Comments

Martin Brandl Over a year ago

You probably don't need the cast here and can omit | ForEach-Object { [int]$_ }

Bacon Bits Over a year ago

Maybe, but I'm on mobile and can't test. Either way, I'd rather not assume that Measure-Object is smart enough to convert strings to ints, or smart enough to evaluate things automagically. "Maximum" and "Minimum" have conventional definitions for strings, after all.

Clijsters Over a year ago

@("1","2", "4", "3") | Measure-Object -Maximum | Select Maximum outputs 4. So yes, the 2nd cast can be omitted.

Bacon Bits Over a year ago

@Clijsters No, that doesn't prove it's not sorting strings. It's definitely doing some form of automagic typing, however, since '1','23','3' returns 23, but '1','23','3','Test' returns Test.

Clijsters Over a year ago

How does your observation conflict with mine? If you put a char to a function for measuring numbers, you will either get an exception (your [int] cast) or it will just calculate the maximum for that String. (One calls it unexpected behavior, I think it's totally ok to do so)

|

Martin Brandl · Accepted Answer · 2017-12-13 05:37:01Z

0

You could use the Measure-Object cmdlet with the -Maximum switch do determine the maximum value after you have removed every new line character from the text file and splitting the values:

(Get-Content numbers.txt -raw) -replace [system.environment]::NewLine, ';' -split ';' |
     Measure-Object -Maximum |
     Select -ExpandProperty Maximum

If your files containing any whitespace character you have to remove them first by adding -replace '\s+' before the first -replace

edited Dec 13, 2017 at 5:37

answered Dec 13, 2017 at 5:30

Martin Brandl

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1 Comment

Dave Sexton Over a year ago

Instead of converting the NewLines to semi-colons how about just expanding your split regex to include them?

Dave Sexton · Accepted Answer · 2017-12-13 11:56:13Z

0

I would use the -raw option of the Get-Content which means the whole thing can be done with a simple regex split. Something like this:

((Get-Content numbers.txt -raw) -split '[\r\n;]+' | Measure-Object -Maximum).Maximum

answered Dec 13, 2017 at 11:56

Dave Sexton

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