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Powershell: Padding a string

Posted on 2013-02-07
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Last Modified: 2013-02-11
I'm reading a csv file that has already process a date in the format MMDDYYYY. However, for single-digit months, there is no leading 0. I'd like to "pad" this string so that there's a leading 0.

I know I can do something like this
$file = import-csv c:\temp\myfile.csv

foreach ($line in $file) {
   $date = $line.DATE 
   if($date.Length -lt 8){
       $date = -Join ("0",$date)
    } else {
        # date length is good; do nothing
    }
}

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I'm looking for the most efficient way to do this (less code as possible)
Thx
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Question by:bndit
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9 Comments
 
LVL 42

Expert Comment

by:sedgwick
ID: 38865453
simply parse the date instead of checking
length and stuff:
$file = import-csv c:\temp\myfile.csv

foreach ($line in $file) {
$date = $line.DATA
$date = [DateTime]::Parse($date).ToString("MMDDYYYY")

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Author Comment

by:bndit
ID: 38865469
what am I doing wrong? See snapshot attached to see how I'm running it (straight on the shell)

Exception calling "Parse" with "1" argument(s): "String was not recognized as a valid DateTime."
At line:1 char:18
+ [DateTime]::Parse <<<< ($date).ToString("MMDDYYYY")
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException
date.png
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LVL 42

Expert Comment

by:sedgwick
ID: 38865634
sorry for the confusion, parse and parseExact can't deal with single digit month even when explicitly defined:
$date = "6102013"
$date = [DateTime]::ParseExact($date, "Mddyyyy",[System.Globalization.CultureInfo]::CurrentCulture) 

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also in several places i found that ppl use similar methods to detect single digits months (or days) and simply pad with 0 to work with DateTime objects.
you can shorten your line by doing this:
$file = import-csv c:\temp\myfile.csv
foreach ($line in $file) {
  [DateTime]$date = @{$true=("0"+$line.DATE);$false=$line.DATE}[$line.DATE.Length -lt 8] 
}                

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Author Comment

by:bndit
ID: 38865715
This article would make me think I could use the static method ParseExact
http://dusan.kuzmanovic.net/2012/05/07/powershell-parsing-date-and-time/

do you know why it's not working?
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Expert Comment

by:sedgwick
ID: 38865813
I tested parseExact it wont work with single digit month
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LVL 68

Expert Comment

by:Qlemo
ID: 38866056
How about
foreach ($line in import-csv c:\temp\myfile.csv) {
   $date = $line.DATE.PadLeft(8, '0') 
}

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or
import-csv c:\temp\myfile.csv | % { $date = $_.Date.PadLeft(8, '0') }

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Author Comment

by:bndit
ID: 38866295
Thanks for trying, but I think it's going to be really hard to convert dates given to me in this format since a 1-digit month and 1-digit day are used. Padding left would yield incorrect dates where the date is 1-digit (i.e. 1271950 would yield 01271950 but I really want 12071950).
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LVL 68

Assisted Solution

by:Qlemo
Qlemo earned 115 total points
ID: 38866324
It is not only hard, it is impossible. Think of 1112013 - is that  01 11 2013 or 11 01 2013 ? I assumed that just the month is missing the leading zero.
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Accepted Solution

by:
Learnctx earned 115 total points
ID: 38866686
It really sounds like the system/application doing the export needs to be rectified rather than production a script or function to compensate for it. I would really investigate why the output is being done incorrectly into the CSV.
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