Powershell 列出一系列日期之间的日期。

Question

I am writing a script in PowerShell and I need to know the dates between a range of dates.

The script is to automate reporting. Let's say there is a bunch of logged data, but the data only gets collected on weekdays, no weekends and no holidays. I FTP and collect the last 15 generations logged.

With the script I open up the latest instance of the report in Excel . Once the workbook has opened up I read a cell which contains a date, that date will determine when the last time the report has been ran on. (Today's data however will not be accessible until tomorrow, so it is always 1 day behind.)

When I than have that date, I use Get-Date to get the current date. I need to know the dates between the current date and the date I read in from Excel. Afterwards I will need to see if any of the dates have fallen on a holiday, or if they have fell on the weekend.

$excelDate = $excel.Cells.Item(1489, 1).Value()
$currentDate = Get-Date 

Let's say $excelDate = "03/07/2014"

and $currentDate = "03/14/2014"

What I would like to get is 03/08/2014, 03/09/2014, 03/10/2014, 03/11/2014, 03/12/2014, 03/13/2014.

Once I have those dates I can check to see if any of them were a holiday, and if they have fallen on a weekend.

If they fell on a holiday I can subtract 1 day (or 2 days if the last day in the report fell on a Friday...I am still trying to figure out how I am going to do this.), and use a switch to get-content of the proper data before I begin to parse through and put it into Excel .

So something like this:

switch($daysMissed)    
        {                                                       
           1  {Write-Host "The Report is currently up to date!!"                       }   
           2  {$data = get-content C:\Users\$userName\Desktop\Report\data\data.txt  }  
           3  {$data = get-content C:\Users\$userName\Desktop\Report\data\data2.txt } 
           4  {$data = get-content C:\Users\$userName\Desktop\Report\data\data3.txt }
           5  {$data = get-content C:\Users\$userName\Desktop\Report\data\data4.txt }
           6  {$data = get-content C:\Users\$userName\Desktop\Report\data\data5.txt }
           7  {$data = get-content C:\Users\$userName\Desktop\Report\data\data6.txt } 
           8  {$data = get-content C:\Users\$userName\Desktop\Report\data\data7.txt } 
           9  {$data = get-content C:\Users\$userName\Desktop\Report\data\data8.txt } 
           10 {$data = get-content C:\Users\$userName\Desktop\Report\data\data9.txt }
           11 {$data = get-content C:\Users\$userName\Desktop\Report\data\data10.txt }
}

Once I have the proper data, I do a bunch of stuff within Excel and finish off that days report, then I would go $daysMissed = $daysMissed - 1 .

So my question is how exactly would I list the dates, between a range of dates?

or, is there an easier way to do what I am doing?

Thanks for the help!

Answer 1

Maybe something like:

$excelDate = get-date "03/07/2014"
$currentDate = get-date "03/14/2014"

for ( $i = $excelDate.AddDays(1); $i -lt $currentDate; $i=$i.AddDays(1) )  { 
    $i.ToShortDateString()
}

Answer 2

Something like this, maybe?

$excelDate = "03/07/2014" 
$currentDate = "03/14/2014"

$start = [Datetime]$excelDate
$end   = [Datetime]$currentDate

While ($start -lt $end)
 {
  $start = $start.AddDays(1)
  $start.ToShortDateString()
 }

3/8/2014
3/9/2014
3/10/2014
3/11/2014
3/12/2014
3/13/2014
3/14/2014

Answer 3

this?

PS C:\ps> [datetime]$a =  "03/07/2014"
PS C:\ps> [datetime]$b =  "03/14/2014"
PS C:\ps> 1..(($b -$a).days-1) | % {$a.AddDays($_)}

sabato 8 marzo 2014 00:00:00
domenica 9 marzo 2014 00:00:00
lunedì 10 marzo 2014 00:00:00
martedì 11 marzo 2014 00:00:00
mercoledì 12 marzo 2014 00:00:00
giovedì 13 marzo 2014 00:00:00

or

PS C:\ps> 1..(($b -$a).days-1) | % {$a.AddDays($_).ToShortDateString()}
08/03/2014
09/03/2014
10/03/2014
11/03/2014
12/03/2014
13/03/2014

Answer 4

Here is another example that writes to a file. You should adjust the $path variable to something that fits your need.

function GenerateDates($beginDate,$EndDate)
{
      $path="c:\temp\data.csv"
      "day,week" | Out-File -Append -LiteralPath $path


      $date=$beginDate
      $week=$beginDate
    Do{
         for($i=1;$i -lt 7;$i++)
         {
             $d1=$date.ToString("yyyy-MM-dd")
             $d2=$week.ToString("yyyy-MM-dd")
             "$d1,$d2" | Out-File  -Append -LiteralPath $path
             $date=$date.AddDays(1)
         }
         $date=$date.AddDays(1)
         $week=$date

    }Until($date -gt $endDate)   

}

$beginDate=[datetime]::Parse("2017-09-10")  
$endDate=[datetime]::Parse("2018-06-10")
GenerateDates $beginDate $endDate

Answer 5

I noticed that few of these snippets actually included the start date in the output. Just remember to call .AddDays() after the output, and to change the -lt to -le (less than to less than equal to).

I do understand that was not the initial question posed, but I had a similar question as OP, hopefully this will assist anyone else with a similar problem (printing all dates within a given range).

Function Build-Calendar() {

    Param (

        [System.DateTime] $PeriodStart,
        [System.DateTime] $PeriodEnd

    )

    while ($PeriodStart -le $PeriodEnd) {
        
        $PeriodStart.ToShortDateString()
        $PeriodStart = $PeriodStart.AddDays(1)

    }
}

$testParameters = @{
    
    PeriodStart = "09/16/2020"
    PeriodEnd = "09/30/2020"

}

Build-Calendar @testParameters

9/16/2020
9/17/2020
9/18/2020
9/19/2020
9/20/2020
9/21/2020
9/22/2020
9/23/2020
9/24/2020
9/25/2020
9/26/2020
9/27/2020
9/28/2020
9/29/2020
9/30/2020

Answer 6

For all those who like something terse and one-line-y, here's a quick/compact solution:

$calendar = ({ param([datetime]$from, [datetime]$to, [int]$i=0) do { $from=$from.AddDays($i++);$from } while ($from -le $to) }).Invoke('2021-01-01', (Get-Date))

...and for anyone who wants this broken down a little, here's the same code on multiple lines:

$calendar = {
    param(
        [datetime]$from
      , [datetime]$to
      , [int]     $i=0
    )
    do {
        $from = $from.AddDays($i++)
        $from
    } while ($from -le $to)
}.Invoke('2021-01-01', (Get-Date))

...and finally with a few comments

$calendar = {                       # assign the results of the rest of the code to $calendar
                                    # & begin an anonymous script block, which we can invoke
    param(                          # begin param declaration
        [datetime]$from             # declare the from datetime param
      , [datetime]$to               # declare the to datetime param
      , [int]     $i=0              # declare the counter/offset for our do-loop, which we
                                    # have a default as 0, which is a shortcut way of declaring
                                    # the variable instead of inside the script block
    )                               # end param declaration
    do {                            # begin the do-while loop
        $from = $from.AddDays($i++) # increment the start date by one day
        $from                       # return this date to the receiving variable
    } while ($from -le $to)         # repeat the do-while if from <= to
}.Invoke('2021-01-01', (Get-Date))  # finally, we invoke the anonymous function and pass in
                                    # our start and end dates