CSV Column Merger

What does the CSV Column Merger do?

The CSV Column Merger combines two selected columns into one single column using a customizable separator (such as a space, hyphen, underscore, slash, or custom characters). It allows in-place replacement (combining first_name and last_name into full_name) or appending the merged column as a new field while preserving RFC 4180 quotation formatting and custom delimiters.

Core Concepts

• Concatenation with Separators: Combines values from column $A$ and column $B$ with custom punctuation or delimiters (e.g. "John" + " " + "Doe" = "John Doe").
• Blank Value Handling: Automatically handles missing or blank fields gracefully without generating dangling or stray separators.
• In-Place or Append Mode: Replaces both original columns in place or preserves them while appending the merged column to the spreadsheet.

How to use the tool?

1. Input CSV Data: Paste your CSV spreadsheet data into the input box or click Load Sample.
2. Configure Merge:
   • First & Second Column: Choose the two distinct columns to combine.
   • Separator: Select Space, Hyphen, Underscore, Slash, Comma, or enter a Custom string.
   • Merged Header: Enter the column header name (e.g. full_name).
   • Keep Original Columns: Check to append rather than replace in place.
3. Merge & Export: Click Merge Columns, then click Copy or Download.

Related Developer Utilities

• CSV Column Duplicator: Duplicate an existing column to a new index.
• CSV Column Extractor: Extract specific columns and discard all others.
• CSV Column Mover: Move one selected column to a different position.

REST API Integration

blueutils.com provides a free REST API endpoint (POST https://blueutils.com/api/csv/csv-column-merger) for programmatic integration.

API Request Parameters

API Request Payload Examples

cURL

curl -X POST https://blueutils.com/api/csv/csv-column-merger \
  -H "Content-Type: application/json" \
  -d '{
    "rawText": "first_name,last_name,department\nAlice,Smith,Engineering\nBob,Jones,Marketing",
    "options": {
      "firstColIndex": 0,
      "secondColIndex": 1,
      "separator": " ",
      "mergedHeaderName": "full_name",
      "keepOriginals": false
    }
  }'

Python

import requests

url = "https://blueutils.com/api/csv/csv-column-merger"
payload = {
    "rawText": "first_name,last_name,department\nAlice,Smith,Engineering\nBob,Jones,Marketing",
    "options": {
        "firstColIndex": 0,
        "secondColIndex": 1,
        "separator": " ",
        "mergedHeaderName": "full_name"
    }
}
headers = {"Content-Type": "application/json"}
response = requests.post(url, json=payload, headers=headers)
print(response.json())

Java

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Main {
    public static void main(String[] args) throws Exception {
        String jsonPayload = "{\"rawText\": \"A,B\\n1,2\", \"options\": {\"firstColIndex\": 0, \"secondColIndex\": 1}}";
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://blueutils.com/api/csv/csv-column-merger"))
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(jsonPayload))
            .build();
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}

API Response Parameters

API Response Payload Examples

Success Response (HTTP 200 OK)

{
  "isValid": true,
  "result": "full_name,department\nAlice Smith,Engineering\nBob Jones,Marketing",
  "headers": ["full_name", "department"],
  "firstColIndex": 0,
  "secondColIndex": 1,
  "mergedHeaderName": "full_name",
  "separator": " ",
  "keepOriginals": false,
  "rowCount": 2,
  "originalColumnCount": 3,
  "finalColumnCount": 2
}

Error Response (HTTP 400 Bad Request)

{
  "isValid": false,
  "error": "Cannot merge a column with itself. Please select two distinct columns."
}

Rate Limit Exceeded Response (HTTP 429 Too Many Requests)

{
  "error": "API rate limit exceeded. Please wait or contact support@blueutils.com."
}

Why use an API to merge CSV columns?

Integrating the CSV Column Merger API into CI/CD pipelines, automated ETL pipelines, or autonomous agent workflows provides several practical advantages:

• Rapid Script Validation: Combine address components (city, state, zip) or contact attributes (first_name, last_name) into canonical attributes prior to database synchronization.
• Optimized Token Efficiency for AI Agents: Executing string concatenations via an API call eliminates token serialization overhead for large tables.
• Deterministic Accuracy Without Hallucinations: Language models can skip missing cells or misalign columns when merging string columns across thousands of records. Delegating processing to a deterministic API guarantees 100% computational accuracy every time without token overhead.

Native Usage

How to achieve the same task locally without external dependencies using native operating system utilities and scripting languages:

Windows (CMD / PowerShell)

Using native PowerShell calculated properties:

# Combine first_name and last_name into full_name
Import-Csv -Path "input.csv" | Select-Object @{Name='full_name';Expression={"$($_.first_name) $($_.last_name)"}}, department | Export-Csv -Path "output.csv" -NoTypeInformation

Linux / Unix (Bash / Shell)

Using standard Linux awk:

# Combine columns 1 and 2 with space
awk -F',' 'NR==1 {print "full_name,"$3; next} {print $1" "$2","$3}' input.csv > output.csv

Python

Using the Python standard library csv module:

import csv

with open("input.csv", mode="r", encoding="utf-8") as infile:
    reader = csv.reader(infile)
    header = next(reader)
    rows = list(reader)

# Replace col 0 & 1 with merged column
new_header = ["full_name"] + header[2:]
new_rows = [[f"{row[0]} {row[1]}".strip()] + row[2:] for row in rows]

with open("output.csv", mode="w", newline="", encoding="utf-8") as outfile:
    writer = csv.writer(outfile)
    writer.writerow(new_header)
    writer.writerows(new_rows)

print("Columns merged successfully.")

Java

Using standard Java java.nio.file.Files:

import java.nio.file.*;
import java.util.*;

public class MergeCsvColumnsExample {
    public static void main(String[] args) throws Exception {
        List<String> lines = Files.readAllLines(Paths.get("input.csv"));
        if (lines.isEmpty()) return;

        List<String> output = new ArrayList<>();
        output.add("full_name," + lines.get(0).split(",", 3)[2]);

        for (int i = 1; i < lines.size(); i++) {
            String[] parts = lines.get(i).split(",", 3);
            output.add((parts[0] + " " + parts[1]).trim() + (parts.length > 2 ? "," + parts[2] : ""));
        }

        Files.write(Paths.get("output.csv"), output);
        System.out.println("Columns merged successfully.");
    }
}