CSV formatting - strip qualifier from specific fields

Question

I am sorry if this question as been asked before, but I couldn't find anything similar.

I am receiving CSV output that uses " as a text qualifier around every field. I am looking for an elegant solution to reformat these so that only specific (alphanumeric fields) have these qualifiers.

An example of what I am receiving:

"TRI-MOUNTAIN/MOUNTAI","F258273","41016053","A","10/16/14",3,"1","Recruit-Navy,XL#28-75","13.25","13.25"

My desired output would be this:

"TRI-MOUNTAIN/MOUNTAI","F258273",41016053,"A",10/16/14,3,1,"Recruit-Navy,XL#28-75",13.25,13.25

Any suggestions or assistance are greatly appreciated!

Per request below find the first five lines of the example file:

"TRI-MOUNTAIN/MOUNTAI","F258273","41016053","","10/16/14","","1","Recruit-Navy,XL#28-75","13.25","13.25"
"TRI-MOUNTAIN/MOUNTAI","F258273","41016053","","10/16/14","","1","High Peak-Navy,XL#21-18","36.75","36.75"
"TRI-MOUNTAIN/MOUNTAI","F257186","Z1023384","","10/15/14","","1","Patriot-Red,L#26-35","25.50","25.50"
"TRI-MOUNTAIN/MOUNTAI","F260780","Z1023658","","10/20/14","","1","Exeter-Red/Gray,S#23-52","19.75","19.75"
"TRI-MOUNTAIN/MOUNTAI","F260780","Z1023658","","10/20/14","","1","Exeter-White/Gray,XL#23-56","19.75","19.75"

Note that this is only an example and not all files will be for Tri-Mountain.

Answer 1

This problem presents the difficulty of separating quotes from comma separated fields where the fields themselves contain embedded commas. (e.g.: "Recruit-Navy,XL#28-75") There are a number of ways to approach this from a shell standpoint (while read, awk, etc.) but most will ultimately stumble on the embedded comma.

One approach found to be successful was a brute force character-by-character parse of the line. (below) This isn't an elegant solution, but it will get you started. The other alternative to a shell program would be a compiled language, such as C, where character handling is a bit more robust. Leave a comment if you have questions.

#!/bin/bash

declare -a arr
declare -i ct=0

## fill array with separated fields (preserving comma in fields)
#  Note: the following is a single-line (w/continuations for readability)
arr=( $( line='"TRI-MOUNTAIN/MOUNTAI","F258273","41016053","A","10/16/14",3,"1","Recruit-Navy,XL#28-75","13.25","13.25"'; \
for ((i=0; i < ${#line}; i++)); do \
    if test "${line:i:1}" == ',' ; then \
        if test "${line:i+1:1}" == '"' -o "${line:i-1:1}" == '"' ; then \
            printf " "; \
        else \
            printf "%c" ${line:i:1}; \
        fi; \
    else \
        printf "%c" ${line:i:1}; \
    fi; \
done; \
printf "\n" ) )

## remove quotes from non-numeric fields
for i in "${arr[@]}"; do 
    if [[ "${i:0:1}" == '"' ]] && [[ ${i:1:1} == [0123456789] ]]; then
        arr[$ct]="${i//\"/}"
    else
        arr[$ct]="$i"
    fi
    if test "$ct" -eq 0 ; then
        printf "%s" "${arr[ct]}"
    else
        printf ",%s" "${arr[ct]}"
    fi
    ((ct++))
done

printf "\n"

exit 0

output

$ bash sepquoted.sh
"TRI-MOUNTAIN/MOUNTAI","F258273",41016053,"A",10/16/14,3,1,"Recruit-Navy,XL#28-75",13.25,13.25

original

"TRI-MOUNTAIN/MOUNTAI","F258273","41016053","A","10/16/14",3,"1","Recruit-Navy,XL#28-75","13.25","13.25"

Answer 2

Since you've not specified OS or language, here is the PowerShell version.

I've ditched my previous attempt to work with Import-CSV because of your non-standard CSV files and switched to raw file processing. Should be significantly faster too.

Regex to split CSV is from this question: How to split a string by comma ignoring comma in double quotes

Save this script as StripQuotes.ps1. It accepts following arguments:

• InPath: folder to read CSVs from. If not specified, the current directory is used.
• OutPath: folder to save processed CSVs to. Will be created, if not exist.
• Encoding: If not specified, script will use system's current ANSI code page to read the files. You can get other valid encodings for your system in PowerShell console like this: [System.Text.Encoding]::GetEncodings()
• Verbose: script will tell you what's going on via Write-Verbose messages.

Example (run from the PowerShell console).

Process all CSVs in the folder C:\CSVs_are_here, save processed CSVs to the folder C:\Processed_CSVs, be verbose:

.\StripQuotes.ps1 -InPath 'C:\CSVs_are_here' -OutPath 'C:\Processed_CSVs' -Verbose

StripQuotes.ps1 script:

Param
(
    [Parameter(ValueFromPipelineByPropertyName = $true)]
    [ValidateScript({
        if(!(Test-Path -LiteralPath $_ -PathType Container))
        {
            throw "Input folder doesn't exist: $_"
        }
        $true
    })]
    [ValidateNotNullOrEmpty()]
    [string]$InPath = (Get-Location -PSProvider FileSystem).Path,

    [Parameter(Mandatory = $true, ValueFromPipelineByPropertyName = $true)]
    [ValidateScript({
        if(!(Test-Path -LiteralPath $_ -PathType Container))
        {
            try
            {
                New-Item -ItemType Directory -Path $_ -Force
            }
            catch
            {
                throw "Can't create output folder: $_"
            }
        }
        $true
    })]
    [ValidateNotNullOrEmpty()]
    [string]$OutPath,

    [Parameter(ValueFromPipelineByPropertyName = $true)]
    [string]$Encoding = 'Default'
)


if($Encoding -eq 'Default')
{
    # Set default encoding
    $FileEncoding = [System.Text.Encoding]::Default
}
else
{
    # Try to set user-specified encoding
    try
    {
        $FileEncoding = [System.Text.Encoding]::GetEncoding($Encoding)
    }
    catch
    {
        throw "Not valid encoding: $Encoding"
    }
}

$DQuotes = '"'
$Separator = ','
# https://stackoverflow.com/questions/15927291/how-to-split-a-string-by-comma-ignoring-comma-in-double-quotes
$SplitRegex = "$Separator(?=(?:[^$DQuotes]|$DQuotes[^$DQuotes]*$DQuotes)*$)"
# Matches a single code point in the category "letter".
$AlphaNumRegex = '\p{L}'

Write-Verbose "Input folder: $InPath"
Write-Verbose "Output folder: $OutPath"

# Iterate over each CSV file in the $InPath
Get-ChildItem -LiteralPath $InPath -Filter '*.csv' |
    ForEach-Object {
        Write-Verbose "Current file: $($_.FullName)"
        $InFile = New-Object -TypeName System.IO.StreamReader -ArgumentList (
            $_.FullName,
            $FileEncoding
        ) -ErrorAction Stop
        Write-Verbose 'Created new StreamReader'

        $OutFile = New-Object -TypeName System.IO.StreamWriter -ArgumentList (
            (Join-Path -Path $OutPath -ChildPath $_.Name),
            $false,
            $FileEncoding
        ) -ErrorAction Stop
        Write-Verbose 'Created new StreamWriter'

        Write-Verbose 'Processing file...'
        while(($line = $InFile.ReadLine()) -ne $null)
        {
            $tmp = $line -split $SplitRegex |
                        ForEach-Object {
                            # Strip double quotes, if any
                            $item = $_.Trim($DQuotes)

                            if($_ -match $AlphaNumRegex)
                            {
                                # If field has at least one letter - wrap in quotes
                                $DQuotes + $item + $DQuotes
                            }
                            else
                            {
                                # Else, pass it as is
                                $item
                            }
                        }
            # Write line to the new CSV file
            $OutFile.WriteLine($tmp -join $Separator)
        }

        Write-Verbose "Finished processing file: $($_.FullName)"
        Write-Verbose "Processed file is saved as: $($OutFile.BaseStream.Name)"

        # Close open files and cleanup objects
        $OutFile.Flush()
        $OutFile.Close()
        $OutFile.Dispose()

        $InFile.Close()
        $InFile.Dispose()
    }