Use batch scripting to replace null values with 0 in a specific column in a CSV

I need to prepare an automatically-generated CSV file for import into a database. One of the columns is supposed to contain integers, but the generating program (which I have no control of) doesn't always put anything in that column. The database import won't accept null values in an integer column. There are other string columns that should stay null.

Here's a simplified CSV with the problem:

"1","Adam","Likes puppies","4451","2014-05-01"

I'd like to replace the "" occurrences with "0" in column 4 only.

I can get as far as being able to isolate the column in each row and set a non-nil substitute variable:

set inputCSV=%1
set outputCSV=%2

for /f "delims==" %%a IN (%inputCSV%) DO (
    set line=%%a
    for /f "tokens=4 delims=," %%b IN ("!line!") DO (
        if %%b=="" (
            set data="0"
        ) else (
            set data=%%b

However, I can't figure out how to output the corrected line to a new file. I was heading towards inserting something like:

if !data!=="0" (
for /f "tokens=1-3 delims=," %%d IN ("!line!") DO set prev=%%d,%%e,%%f
for /f "tokens=5 delims=," %%g IN ("!line!") DO set next=%%g
echo !prev!,!data!,!next! >> %outputCSV%
) else (
echo !line! >> %outputCSV%

But the real CSV has dozens of columns, so I'm going to run out of FOR variables, and it just seems like there's a better way I can't see ...

Any insight would be appreciated.


use tokens=1-4,*

* means "the fifth token is the rest of the line"

Complete code:

@echo off
setlocal enabledelayedexpansion
set inputCSV=%1
set outputCSV=%2

(for /f "tokens=1-4,* delims=," %%a IN (%inputCSV%) DO (
    if "%%d"=="""" (set "value="000"") else (set "value=%%d")
    echo %%a,%%b,%%c,!value!,%%e

EDIT for the additional info in the comment

@echo off
setlocal enabledelayedexpansion
set inputCSV=%1
set outputCSV=%2

(for /f "tokens=*" %%a IN (%inputCSV%) DO (
  set column=0
  set "line="
  for %%i in ( %%a ) do ( 
    set /a column+=1
    set value=%%~i
    if !column!==4 (   
      if "!value!"=="" set "value=0"
    set "line=!line!,"!value!"" 
  echo !line:~1!

change the 4 to the correct column number.

Attention: there is a limit for the number of characters per line (don't remember how much, could affect %%a)

Also some special characters will make trouble.

This should be a robust and quick way to do it:

This uses a helper batch file called repl.bat (by dbenham) - download from:

Place repl.bat in the same folder as the batch file or in a folder that is on the path.

@echo off
type "file.csv" | repl "^(.*?,.*?,.*?),\q\q,(.*)" "$1,\q0\q,$2" x >"newfile.csv"

Need Your Help

How can I tell if someone is a friend of mine in Facebook Graph API V2.0 and above?

facebook facebook-graph-api facebook-graph-api-v2.0 facebook-friends

In my App, I go through different groups and pages, and check public posts that were posted by people that haven't installed my App.

Valid batch file variable names?

file variables batch-file numbers numeric

I have the following problem with batch files. I simplify the problem below.

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.