csv-kit

CSV reading and writing for Kotlin with streaming support.

Installation

Gradle (Kotlin DSL)

implementation("com.philiprehberger:csv-kit:0.2.0")

Maven

<dependency>
    <groupId>com.philiprehberger</groupId>
    <artifactId>csv-kit</artifactId>
    <version>0.2.0</version>
</dependency>

Usage

Quick Read

import com.philiprehberger.csvkit.*

val rows = Csv.read("name,age\nAlice,30\nBob,25")
rows.forEach { row ->
    println("${row["name"]} is ${row["age"]} years old")
}

CsvReader with Configuration

val reader = CsvReader(CsvConfig(
    delimiter = ';',
    skipEmptyLines = true
))

val rows = reader.read("name;age\nAlice;30\n\nBob;25")

Streaming Large Data

val reader = CsvReader()
reader.stream(largeCsvString)
    .filter { it["status"] == "active" }
    .take(100)
    .forEach { row -> process(row) }

Writing CSV

val data = listOf(
    mapOf("name" to "Alice", "age" to "30"),
    mapOf("name" to "Bob", "age" to "25")
)

val output = Csv.write(data, listOf("name", "age"))
// name,age
// Alice,30
// Bob,25

Quoted Fields

The parser handles RFC 4180 compliant quoting: embedded commas, newlines, and escaped quotes.

val csv = """name,bio
Alice,"Loves coding, hiking"
Bob,"Said ""hello"""
"""
val rows = Csv.read(csv)
println(rows[0]["bio"]) // Loves coding, hiking
println(rows[1]["bio"]) // Said "hello"

Typed Accessors

val rows = Csv.read("name,age,active\nAlice,30,true")
val age: Int? = rows[0].getInt("age")        // 30
val active: Boolean? = rows[0].getBoolean("active") // true
val score: Double? = rows[0].getDouble("score")     // null

Trim Fields

val reader = CsvReader(CsvConfig(trimFields = true))
val rows = reader.read("name , age \n Alice , 30 ")
println(rows[0]["name"]) // "Alice" (trimmed)

Header Validation

val reader = CsvReader()
reader.validateHeaders(csvInput, listOf("name", "email", "age"))
// Throws IllegalArgumentException if any header is missing

API

Class / Function	Description
Csv.read(input, config)	Convenience method to parse a CSV string
Csv.write(rows, headers, config)	Convenience method to write maps to CSV
CsvReader	Full-featured CSV parser with read(), readFromFile(), stream()
CsvWriter	CSV writer with write() and writeToFile()
CsvRow	A single row with get(column), get(index), getOrNull(column)
CsvConfig	Configuration: delimiter, quote char, header mode, empty line handling
CsvRow.getInt(column)	Get field as Int or null
CsvRow.getDouble(column)	Get field as Double or null
CsvRow.getBoolean(column)	Get field as Boolean or null
CsvReader.validateHeaders()	Validate expected columns exist
CsvConfig.trimFields	Auto-trim whitespace from field values

Development

./gradlew test       # Run tests
./gradlew check      # Run all checks
./gradlew build      # Build JAR

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License

MIT