CSV.swift

CSV reading and writing library written in Swift.

Usage for reading CSV

From string

import CSV

let csvString = "1,foo\n2,bar"
let csv = try! CSVReader(string: csvString)
while let row = csv.next() {
    print("\(row)")
}
// => ["1", "foo"]
// => ["2", "bar"]

From file

NOTE: The default character encoding is UTF8.

import Foundation
import CSV

let stream = InputStream(fileAtPath: "/path/to/file.csv")!
let csv = try! CSVReader(stream: stream)
while let row = csv.next() {
    print("\(row)")
}

Getting the header row

import CSV

let csvString = "id,name\n1,foo\n2,bar"
let csv = try! CSVReader(string: csvString,
                         hasHeaderRow: true) // It must be true.

let headerRow = csv.headerRow!
print("\(headerRow)") // => ["id", "name"]

while let row = csv.next() {
    print("\(row)")
}
// => ["1", "foo"]
// => ["2", "bar"]

Get the field value using subscript

import CSV

let csvString = "id,name\n1,foo"
let csv = try! CSVReader(string: csvString,
                         hasHeaderRow: true) // It must be true.

while csv.next() != nil {
    print("\(csv["id"]!)")   // => "1"
    print("\(csv["name"]!)") // => "foo"
}

Provide the character encoding

If you use a file path, you can provide the character encoding to initializer.

import Foundation
import CSV

let stream = InputStream(fileAtPath: "/path/to/file.csv")!
let csv = try! CSVReader(stream: stream,
                         codecType: UTF16.self,
                         endian: .big)

Reading a row into a Decodable object

If you have a destination object that conforms to the Decodable protocol, you can serialize a row with a new instances of the object.

struct DecodableExample: Decodable {
    let intKey: Int
    let stringKey: String
    let optionalStringKey: String?
}

let csv = """
    intKey,stringKey,optionalStringKey
    1234,abcd,
    """

var records = [DecodableExample]()
do {
    let reader = try CSVReader(string: csv, hasHeaderRow: true)
    let decoder = CSVRowDecoder()
    while reader.next() != nil {
        let row = try decoder.decode(DecodableExample.self, from: reader)
        records.append(row)
    }
} catch {
    // Invalid row format
}

Usage for writing CSV

Write to memory and get a CSV String

NOTE: The default character encoding is UTF8.

import Foundation
import CSV

let csv = try! CSVWriter(stream: .toMemory())

// Write a row
try! csv.write(row: ["id", "name"])

// Write fields separately
csv.beginNewRow()
try! csv.write(field: "1")
try! csv.write(field: "foo")
csv.beginNewRow()
try! csv.write(field: "2")
try! csv.write(field: "bar")

csv.stream.close()

// Get a String
let csvData = csv.stream.property(forKey: .dataWrittenToMemoryStreamKey) as! Data
let csvString = String(data: csvData, encoding: .utf8)!
print(csvString)
// => "id,name\n1,foo\n2,bar"

Write to file

NOTE: The default character encoding is UTF8.

import Foundation
import CSV

let stream = OutputStream(toFileAtPath: "/path/to/file.csv", append: false)!
let csv = try! CSVWriter(stream: stream)

try! csv.write(row: ["id", "name"])
try! csv.write(row: ["1", "foo"])
try! csv.write(row: ["1", "bar"])

csv.stream.close()

Installation

Swift Package Manager

Add the dependency to your Package.swift. For example:

// swift-tools-version: 5.9

import PackageDescription

let package = Package(
    name: "MyPackage",
    dependencies: [
        // Add `CSV.swift` package here.
        .package(url: "https://github.com/yaslab/CSV.swift.git", from: "2.5.2")
    ],
    targets: [
        .executableTarget(
            name: "MyCommand",
            dependencies: [
                // Then add it to your module's dependencies.
                .product(name: "CSV", package: "CSV.swift")
            ]
        )
    ]
)

CocoaPods

pod 'CSV.swift', '~> 2.5.2'

Reference specification

• RFC4180 (en, ja)

License

CSV.swift is released under the MIT license. See the LICENSE file for more info.