比较两个csv文件中的列

Question

With all of the examples out there you would think I could have found my solution. :-)

Anyway, I have two csv files; one with two columns, one with 4. I need to compare one column from each one using powershell. I thought I had it figured out but when I did a compare of my results, it comes back as false when I know it should be true. Here's what I have so far:

 $newemp = Import-Csv -Path "C:\Temp\newemp.csv" -Header login_id, lastname, firstname, other | Select-Object "login_id"
 $ps = Import-Csv -Path "C:\Temp\Emplid_LoginID.csv" | Select-Object "login id"
 If ($newemp -eq $ps)
    {
      write-host "IDs match" -forgroundcolor green
    }
 Else 
    {
      write-host "Not all IDs match" -backgroundcolor yellow -foregroundcolor black
    }

I had to specifiy headers for the first file because it doesn't have any. What's weird is that I can call each variable to see what it holds and they end up with the same info but for some reason still comes up as false. This occurs even if there is only one row (not counting the header row).

I started to parse them as arrays but wasn't quite sure that was the right thing. What's important is that I compare row1 of the first file with with row1 of the second file. I can't just do a simple -match or -contains.

EDIT: One annoying thing is that the variables seem to hold the header row as well. When I call each one, the header is shown. But if I call both variables, I only see one header but two rows.

I just added the following check but getting the same results (False for everything):

    $results = Compare-Object -ReferenceObject $newemp -DifferenceObject $ps -PassThru | ForEach-Object { $_.InputObject }

Answer 1

Using latkin's answer from here I think this would give you the result set you're looking for. As per latkin's comment, the property comparison is redundant for your purposes but I left it in as it's good to know. Additionally the header is specified even for the csv with headers to prevent the header row being included in the comparison.

$newemp = Import-Csv -Path "C:\Temp\_sotemp\Book1.csv" -Header loginid | 
    Select-Object "loginid"

$ps = Import-Csv -Path "C:\Temp\_sotemp\Book2.csv" -Header loginid | 
    Select-Object "loginid"

#get list of (imported) CSV properties
$props1 = $newemp | gm -MemberType NoteProperty | select -expand Name | sort
$props2 = $ps | gm -MemberType NoteProperty | select -expand Name | sort

#first check that properties match 
#omit this step if you know for sure they will be
if(Compare-Object $props1 $props2){
    throw "Properties are not the same! [$props1] [$props2]"
}

#pass properties list to Compare-Object
else{
    Compare-Object $newemp $ps -Property $props1
}

Answer 2

In the second line, I see there a space "login id" and the first line doesn't have it. Could that be an issue. Try having the same name for the headers in the .csv files itself. And it works for without providing header or select statements. Below is my experiment based upon your input.

emp.csv

loginid      firstname  lastname
------------------------------
abc123   John       patel  
zxy321   Kohn       smith  
sdf120   Maun       scott  
tiy123   Dham       rye  
k2340    Naam       mason  
lk10j5   Shaan      kelso  
303sk    Doug       smith  

empids.csv

loginid
-------  
abc123  
zxy321  
sdf120  
tiy123  

PS C:\\>$newemp = Import-csv C:\\scripts\\emp.csv
PS C:\\>$ps = Import-CSV C:\\scripts\\empids.csv
PS C:\\>$results = Compare-Object -ReferenceObject $newemp -DifferenceObject $ps | foreach { $_.InputObject}

Shows the difference objects that are not in $ps

loginid  firstname  lastname   SideIndicator  
-------  ---------  --------   -------------  
k2340    Naam       mason      <=  
lk10j5   Shaan      kelso      <=  
303sk    Doug       smith      <=  

Answer 3

I am not sure if this is what you are looking for but i have used the PowerShell to do some CSV formatting for myself.

            $test = Import-Csv .\Desktop\Vmtools-compare.csv
                foreach ($i in $test) {
                    foreach ($n in $i.name) {    
                        foreach ($m in $test) {
                            $check = "yes"         
                            if ($n -eq $m.prod) {
                                $check = "no"
                                break
                            }
                        }
                    if ($check -ne "no") {$n}
                    }
                }

this is how my excel csv file looks like:

prod    name
1       3
2       5
3       8
4       2
5       0

and script outputs this:

8
0

so basically script takes each number under Name column and then checks it against prod column. If the number is there then it won't display else it will display that number.

I have also done it the opposite way:

        $test = Import-Csv c:\test.csv                
            foreach ($i in $test) {
                foreach ($n in $i.name) {                    
                    foreach ($m in $test) {
                        $check = "yes"                         
                        if ($n -eq $m.prod) {echo $n}
                    }
                }
            }

this is how my excel csv looks like:

prod    name
1       3
2       5
3       8
4       2
5       0

and script outputs this:

3
5
2

so script shows the matching entries only.

You can play around with the code to look at different columns.