Find first available serial based on list of strings?

Question

Given a list of strings such as: apple01, apple02, and apple04, banana02, cherry01, how would you come up with t

Answer 1

This seems to do the trick!

## Create variable to store number in 
$spareNumber = $null 
## we are presuming that they have already been seperated into groups 
$apples = @("apples01","apples002","apples3","apples15") 
## create an empty array 
$num = @() 
## You know what a foreach is right? ;) 
foreach ($apple in $apples)
{
    ## the hard working part 
    ## [convert]:: toint32 converts to, you guessed it... (and adds it to $num)
    ## $apple -split ($apple -split '\d+$') < split all digits from end, then strip off everything at the front 
    $num += [convert]::ToInt32([string]$($apple -split ($apple -split '\d+$'))[1], 10)
}
## count from 1 to 10, and pass to foreach 
(1..10) | foreach {
    ##'when we find one that isn't in $num, store it in sparenumber and break out of this joint. 
    if (!$num.Contains($_)) {
        $spareNumber = $_ 
        break 
    }
 }
 ## and here is your number... 
 $spareNumber