Combining Multiple CSV Files

merge multiple csv files into one python
merge csv files mac
combine multiple csv files into one workbook separate sheets
merge csv files linux
merge csv files powershell
merge csv files without header
csv merge software
merge multiple text files into one notepad++

So I've been assaulting the internet all day looking for a way to combine multiple CSV files. I keep running into an issue, no matter which of the 30+ PowerShell approaches I've looked up.

I'm trying to combine multiple CSV files into one, essentially in "full join" style. I need to end up with all rows and all columns from all CSVs combined, with the exception that I want to combine rows based on a common identifier. This discussion: "Merging two CSV files by shared column", does exactly what I'm looking to do with two exceptions. First it's only built for two CSVs and second it drops rows if both CSVs don't contain the "Name". I'd like to keep the row even if it's not in both CSVs and simply create blank entries where there is no data in the other CSV.

CSV1.csv

Name,Attrib1,Attrib2

VM1,111,True
VM2,222,False

CSV2.csv

Name,AttribA,Attrib1

VM1,AAA,111
VM3,CCC,333

CSV3.csv

Name,Attrib2,AttribB

VM2,False,YYY
VM3,True,ZZZ

Desired combined result:

Name,Attrib1,Attrib2,AttribA,AttribB

VM1,111,True,AAA,
VM2,222,False,,YYY
VM3,333,True,CCC,ZZZ

Anyone have any ideas on this one? If you need more info from my end just let me know.

Update: Here's my current code attempt with the SQLite shell:

$db  = Join-Path $env:TEMP 'temp.db'
$dir = "C:\Users\UserName\Downloads\CSV Combination"
$outfile = Join-Path $dir 'combined.csv'

@"
CREATE TABLE a (Name varchar(20),OS varchar(20),IP varchar(20),Contact varchar(20),Application varchar(20));
CREATE TABLE b (Name varchar(20));
CREATE TABLE c (Name varchar(20),Quiesce varchar(20));
CREATE TABLE d (Name varchar(20),NoQuiesce varchar(20));
.mode csv
.import '$((Join-Path $dir csv1.csv) -replace '\\', '\\')' a
.import '$((Join-Path $dir csv2.csv) -replace '\\', '\\')' b
.import '$((Join-Path $dir csv3.csv) -replace '\\', '\\')' c
.import '$((Join-Path $dir csv4.csv) -replace '\\', '\\')' d
SELECT a.Name,a.OS,a.IP,a.Contact,a.Application,c.Quiesce,d.NoQuiesce
FROM a
  LEFT OUTER JOIN b ON a.Name = b.Name
  LEFT OUTER JOIN c ON a.Name = c.Name
  LEFT OUTER JOIN d ON a.Name = d.Name
UNION
SELECT b.Name,a.OS,a.IP,a.Contact,a.Application,c.Quiesce,d.NoQuiesce
FROM b
  LEFT OUTER JOIN a ON a.Name = b.Name
  LEFT OUTER JOIN c ON b.Name = c.Name
  LEFT OUTER JOIN d ON c.Name = d.Name
UNION
SELECT c.Name,a.OS,a.IP,a.Contact,a.Application,c.Quiesce,d.NoQuiesce
FROM c
  LEFT OUTER JOIN a ON a.Name = c.Name
  LEFT OUTER JOIN b ON b.Name = c.Name
  LEFT OUTER JOIN d ON c.Name = d.Name;
"@ | filesystem::"C:\Users\UserName\Downloads\CSV Combination\sqlite3.exe" $db >$outfile

Remove-Item $db

This currently returns the following error message:

sqlite3.exe : Error: C:\Users\brandon.andritsch\Downloads\CSV Combination\csv1.csv line 1: expected 5 columns of data but found 6

I have created a Join-Object proxy command called Merge-Object (alias Merge) as it appeared that merging objects slightly similar to the SQL MERGE statement is often used. The default parameters for the Merge-Object command are set to: JoinType = 'Full' and Property= {{If ($Null -ne $RightIndex) {$Right.$_} Else {$Left.$_}}}}. Meaning that all the left objects are updated with the right property values and right objects that do not exist in left object list are added to the result:

Import-Csv CSV1.csv | 
Merge (Import-Csv CSV2.csv) -On Name | 
Merge (Import-Csv CSV3.csv) -On Name |
Format-Table

Result:

Name Attrib1 Attrib2 AttribA AttribB
---- ------- ------- ------- -------
VM1  111     True    AAA
VM2  222     False           YYY
VM3  333     True    CCC     ZZZ

Merge CSV files online into one file, (for help how to do that enter "help cd") Option 1 – CSV files without a header row. The following single command line will combine all CSV files in the folder as a single file titled ‘combined.csv’. copy *.csv combined.csv. If you want to run this from a cmd file, copy the following contents into a text file and save as ‘run.cmd’.

Try this:

$db  = Join-Path $env:TEMP 'temp.db'
$dir = "C:\some\folder"
$outfile = Join-Path $dir 'combined.csv'

@"
CREATE TABLE a (Name varchar(20),Attrib1 varchar(20),Attrib2 varchar(20));
CREATE TABLE b (Name varchar(20),AttribA varchar(20),Attrib1 varchar(20));
CREATE TABLE c (Name varchar(20),Attrib2 varchar(20),AttribB varchar(20));
.mode csv
.import '$((Join-Path $dir csv1.csv) -replace '\\', '\\')' a
.import '$((Join-Path $dir csv2.csv) -replace '\\', '\\')' b
.import '$((Join-Path $dir csv3.csv) -replace '\\', '\\')' c
SELECT a.Name,a.Attrib1,a.Attrib2,b.AttribA,c.AttribB
FROM a
  LEFT OUTER JOIN b ON a.Name = b.Name
  LEFT OUTER JOIN c ON a.Name = c.Name
UNION
SELECT b.Name,a.Attrib1,a.Attrib2,b.AttribA,c.AttribB
FROM b
  LEFT OUTER JOIN a ON a.Name = b.Name
  LEFT OUTER JOIN c ON b.Name = c.Name
UNION
SELECT c.Name,a.Attrib1,a.Attrib2,b.AttribA,c.AttribB
FROM c
  LEFT OUTER JOIN a ON a.Name = c.Name
  LEFT OUTER JOIN b ON b.Name = c.Name;
"@ | sqlite3 $db >$outfile

Remove-Item $db

You need the SQLite command-line shell for this.

How to combine multiple CSV files into one using CMD – Tom Nash, Type exit and hit enter to close the DOS window. Use pandas to concatenate all files in the list and export as CSV. The output file is named “combined_csv.csv” located in your working directory. #combine all files in the list combined_csv = pd.concat([pd.read_csv(f) for f in all_filenames ]) #export to csv combined_csv.to_csv("combined_csv.csv", index=False, encoding='utf-8-sig')

you could use a great commandline tool: Miller (http://johnkerl.org/miller/doc/).

With

mlr --csv reshape -r "^A" -o item,value then reshape -s item,value \
then unsparsify --fill-with ""  *.csv

You have

Name,Attrib1,Attrib2,AttribA,AttribB
VM1,111,True,AAA,
VM2,222,False,,YYY
VM3,333,True,CCC,ZZZ

As input I have used these 3 files

Name,Attrib1,Attrib2
VM1,111,True
VM2,222,False

Name,Attrib2,AttribB
VM2,False,YYY
VM3,True,ZZZ

Name,AttribA,Attrib1
VM1,AAA,111
VM3,CCC,333

There is also the win exe https://github.com/johnkerl/miller/releases

How to merge or combine multiple files, Merge multiple CSV files in just three simple steps. Click Select CSV-files or pull your files onto the Drag & Drop field to begin with the merging. The CSV files are now getting prepared for the combining. You are now able to change the order how the CSV files will be added to the new merged CSV. Thats it! A CSV file, as the name suggests, combines multiple fields separated by commas. The first row contains the name or title of each column, and remaining rows contain the actual data values. Merge Multiple CSV Files in Python Merge Multiple CSV Files

How to Merge Multiple CSV Files and Combine Them Into One , This is a trick which can save you a lot of time when working with a dataset spread across multiple CSV files. Using a simple CMD command it� A FOLDER OF EXCEL FILES? As I write this, the ability to combine a folder of Excel files isn’t available in Power Query. Unlike CSV files, the data in Excel files can be spread across multiple sheets, so the process is more difficult. Microsoft will eventually add this feature.

Merge CSV files or TXT files in a folder, How to Merge Multiple CSV Files and Combine Them Into One Large CSV File. If you work with a lot of data either personally or as part of your� Type in the following command to merge all CSV files in the folder into a new CSV file titled "newfile.csv" (any name could be used). copy *.csv newfile.csv. After the new file is created, open the new CSV file in Microsoft Excel and save it as an Excel file. Merge a text (.txt) file in the Windows command line

How to merge multiple csv files into one using Command Prompt , How to merge CSV files or TXT files in a folder into a single file. Consolidate multiple CSV or TXT files using VBA, Windows Cmd or MS Query. Hi All, As a coding newbie I am struggling to combine 70 csv files into one. I also need the new file to include an additional (first) column to indicate which original csv file the respective rows came from (i.e. participant number). I've tried the following, but I think it doesn't work because the original file names don't have subject numbers (i.e. only 4 columns), and I'm not sure how to

Comments
  • You might use the [Join-Object] cmdlet from the PowerShell Gallery for this: Import-CSV .\CSV1.csv | Join (Import-CSV .\CSV2.csv) Hosts {$Right.$_} | Join (Import-CSV .\CSV3.csv) Hosts {$Right.$_} | Export-CSV .\combined.csv
  • Hey Ansgar, thanks for the script on this, I don't know that I'll be able to get SQLite setup, I don't have the permissions to actually place it in the System32 dir. I was able to get it to run (I think) using local profile directory, here's the error I had returned to me: sqlite3.exe : Error: unknown command or invalid arguments: "import". Enter ".help" for help
  • The command-line shell is a Zip archive with a single executable. Simply extract it to a directory in your %PATH%. As for the error: the command is .import, not import.
  • .import $((Join-Path $dir csv1.csv) -replace '\\', '\\') a .import $((Join-Path $dir csv2.csv) -replace '\\', '\\') b .import $((Join-Path $dir csv3.csv) -replace '\\', '\\') c These were the commands I used - I'm not sure what %PATH% refers to, I don't see a variable following that and when it's located in the current working directory it errors with the following: The term 'sqlite3.exe' is not recognized as the name of a cmdlet, function, script file, or operable program. Also is there no way to format this comment text? This is awful looking.
  • Ok, I've updated with what I'm seeing. I added a fourth CSV into the mix. One of the concerns I'd have with this method is I'll need to build a custom script whenever the attributes or CSVs change. This will be something I may need to do often and in different ways. I also added in a link to a Discussion I had mentioned that works correctly minus the two details.
  • Also, I noticed that I butchered that code in the middle and skipped a portion when I rewrote. I think I get the idea though, I'll see if I can manage to unbutcher that. (I'm not very familiar with coding, I'm in my early learning phase haha).