Hello PowerShellers,

How do I return the index value of an associative array?

I'm referencing "Pro Windows PowerShell" by Hristo Deshev, p. 18-24

Problem 1: Array and Collection

PS C:\> $a = (1,2,3)
PS C:\> $a[2] # return the value 3 since PowerShell array indexs start
at 0
PS C:\> $a = @("Solaris","Windows","Mac") # works

How would I query $a for "Windows" and return the array index, which is 1?

Problem 2: Dictionaries and Hash Tables

PS C:\> $b = @{1="Solaris"; 2="Windows", 3="Mac"} # doesn't work
PS C:\> $b = @{1 = "Solaris"; 2 = "Windows", 3 = "Mac"} # works
PS C:\> $b.Keys # returns 3,2,1
PS C:\> $b.Values # returns Mac, Windows, Solaris
PS C:\> $b[0] # doesn't return anything, must not use an array index
PS C:\> $b[2] # returns Windows
PS C:\> $b["Windows"] # doesn't return 2, why?

How do I query $b using the value to determine the name/key?

Problem 3: Import-CSV cmdlet (not sure if technical name is associative array)
Given the following CSV file called os.csv
ID,OS,Company
1,Solaris,Sun
2,Windows,Microsoft
3,Mac,Apple

PS C:\> $c = Import-Csv os.csv
PS C:\> $c # will return a table view of os.csv
PS C:\> $c.Keys # doesn't return anything
PS C:\> $c.Values # doesn't return anything
PS C:\> $c[1] # returns the record - 2,Windows,Microsoft
PS C:\> $c[-1] # returns the last record - 3,Mac,Apple
PS C:\> $c[0..2] # returns all records
PS C:\> $c[0..-1] # doesn't return all records, why? Just returns 1st and last
PS C:\> $c | Select-Object OS # will return the OS Field/Column
PS C:\> $c | Where-Object {$_.OS -eq "Windows"} # will return record
2,Windows,Microsoft

So how do I query $c to return the index of the associative array?

Thanks for the help,

Jeff

# 3: Array of psObjects
$c = ipcsv x\os.csv
# get the index for each element whose OS property is -eq to $pattern
$i = 0..($c.length - 1) | ? {$c[$_].OS -eq $pattern}
# retrieve the element(s) using _array_ notation
$c[$i].OS

--
Kiron

Jeff,

There is no direct mapping from a value in an array, hashtable, CSV file,
database, ... to the index, key, "noteproperty", query in any language that
I'm familiar with.

Values are not unique only keys, indices, ... If you really need to look
both ways one idea in Powershell is to assoicate a noteproperty with the
value that equals the index. Kiron has another solution which is simpiler
and likely better for most cases.

"Jeffery Jensen" wrote:
[..]