Matching Swift Strings by Prefix or Suffix

Last Run on XCODE 11.4 / Swift 5.2

A simple way to check if a string starts or ends with a certain pattern is to use the method hasSuffix and hasPrefix available to Strings.

In the code snippet below, we will check if a string begins or ends with a specific text pattern.

let fileName1 = "InstagramCover.jpg"
let fileName2 = "SnapchatCover.doc"

fileName1.hasSuffix("jpg") // result --> True
fileName2.hasSuffix("jpg") // result --> False

fileName1.hasPrefix("Instagram") // --> True
fileName2.hasPrefix("Facebook") // result --> False

If we need to check against multiple variations, we can’t just use hasSuffix. Instead, we will have to use it along with another method contains. Checkout the code snippet below.

let fileName1 = "InstagramCover.png"
let fileName2 = "SnapchatCover.doc"

let fileExtensions = ["jpg", "jpeg", "png"]
let socialMediaNameFilePrefixes = ["Instagram", "Facebook", "Twitter"]

fileExtensions.contains(where: fileName1.hasSuffix) // result --> True
fileExtensions.contains(where: fileName2.hasSuffix) // result --> False

socialMediaNameFilePrefixes.contains(where: fileName1.hasPrefix) // result --> True
socialMediaNameFilePrefixes.contains(where: fileName2.hasPrefix) // result --> False