How to Trim a String in Swift Based on a Character

How to Trim a String in Swift based on a character

You can use String method rangeOfString:

let link = "https://s3.amazonaws.com/brewerydbapi/beer/RXI2cT/upload_FfAPfl-icon.png"
if let range = link.rangeOfString("_") {
    let fileName = link.substringFromIndex(range.endIndex)
    print(fileName)  // "FfAPfl-icon.png\n"
}

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Xcode 8 beta 3 • Swift 3

if let range = link.range(of: "_") {
    let fileName = link.substring(from: range.upperBound)
    print(fileName) // "FfAPfl-icon.png\n"
}

How to trim first 3 character from a string in swift

You can split your string where separator is a slash, drop the first component and then join it again:

let str = "66/001/0004"
let trimmed = str.split { $0 == "/" }
    .dropFirst()
    .joined(separator: "/")   // "001/0004"

Another option is to find the first slash index and get the substring after it:

if let index = str.firstIndex(of: "/") {
    let trimmed = str[str.index(after: index)...]   //  "001/0004"
     // or simply dropping the first character
     // let trimmed = str[index...].dropFirst()
}

Trimming a String inside a loop in Swift 5

You can extend String to give you this functionality (or extract it).

extension String {
    func truncate(to limit: Int, ellipsis: Bool = true) -> String {
        if count > limit {
            let truncated = String(prefix(limit)).trimmingCharacters(in: .whitespacesAndNewlines)
            return ellipsis ? truncated + "\u{2026}" : truncated
        } else {
            return self
        }
    }
}

let default = "Coming up with this sentence was the hardest part of this.".truncate(to: 50)
print(default) // Coming up with this sentence was the hardest part…

let modified = "Coming up with this sentence was the hardest part of this.".truncate(to: 50, ellipsis: false)
print(modified) // Coming up with this sentence was the hardest part

And in your use case:

router.get("/admin", handler: { (request, response, next)  in
    let documents = try collection.find()
    var pages: [[String: String]] = []
    
    for d in documents {
        let truncatedBody = d.body.truncate(to: 50)
        pages.append(["title": d.title, "slug": d.slug, "body": truncatedBody, "date": d.date])
    }
    
    ...
})

Trimming Substrings from String Swift/SwiftUI

A possible way is Regular Expression

let string = "Chest Stretch (left)"
let trimmedString = string.replacingOccurrences(of: "\\s\\([^)]+\\)", with: "", options: .regularExpression)

The found pattern will be replaced with an empty string.

The pattern is:

• One whitespace character \\s
• An opening parenthesis \\(
• One or more characters which are not a closing parentheses [^)]+
• and a closing parenthesis \\)

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Or simpler if the delimiter character is always the opening parenthesis

let trimmedString = String(string.prefix(while: {$0 != "("}).dropLast())

Or

let trimmedString = string.components(separatedBy: " (").first!

Get the string up to a specific character

Expanding on @appzYourLife answer, the following will also trim off the whitespace characters after removing everything after the @ symbol.

import Foundation

var str = "hello, how are you @tom"

if str.contains("@") {
    let endIndex = str.range(of: "@")!.lowerBound
    str = str.substring(to: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
}
print(str) // Output - "hello, how are you"

UPDATE:

In response to finding the last occurance of the @ symbol in the string and removing it, here is how I would approach it:

var str = "hello, how are you @tom @tim?"
if str.contains("@") {
    //Reverse the string
    var reversedStr = String(str.characters.reversed())
    //Find the first (last) occurance of @
    let endIndex = reversedStr.range(of: "@")!.upperBound
    //Get the string up to and after the @ symbol
    let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

    //Store the new string over the original
    str = String(newStr.characters.reversed())
    //str = "hello, how are you @tom"
}

Or looking at @appzYourLife answer use range(of:options:range:locale:) instead of literally reversing the characters

var str = "hello, how are you @tom @tim?"
if str.contains("@") {
    //Find the last occurrence of @
    let endIndex = str.range(of: "@", options: .backwards, range: nil, locale: nil)!.lowerBound
    //Get the string up to and after the @ symbol
    let newStr = str.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

    //Store the new string over the original
    str = newStr
    //str = "hello, how are you @tom"
}

As an added bonus, here is how I would approach removing every @ starting with the last and working forward:

var str = "hello, how are you @tom and @tim?"
if str.contains("@") {

    while str.contains("@") {
        //Reverse the string
        var reversedStr = String(str.characters.reversed())
        //Find the first (last) occurance of @
        let endIndex = reversedStr.range(of: "@")!.upperBound
        //Get the string up to and after the @ symbol
        let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)

        //Store the new string over the original
        str = String(newStr.characters.reversed())
    }
    //after while loop, str = "hello, how are you"
}

Trim String before specific character?

Get the first index of the dot and get the substring after that index

let str = "asderwt.qwertyu.zxcvbbnnhg"
if let index = str.firstIndex(where: { $0 == "." }) {
    print(str[index...])//.qwertyu.zxcvbbnnhg
}

Does swift have a trim method on String?

Here's how you remove all the whitespace from the beginning and end of a String.

(Example tested with Swift 2.0.)

let myString = "  \t\t  Let's trim all the whitespace  \n \t  \n  "
let trimmedString = myString.stringByTrimmingCharactersInSet(
    NSCharacterSet.whitespaceAndNewlineCharacterSet()
)
// Returns "Let's trim all the whitespace"

(Example tested with Swift 3+.)

let myString = "  \t\t  Let's trim all the whitespace  \n \t  \n  "
let trimmedString = myString.trimmingCharacters(in: .whitespacesAndNewlines)
// Returns "Let's trim all the whitespace"

Remove the first six characters from a String (Swift)

length is the number of characters you want to remove (6 in your case)

extension String {

  func toLengthOf(length:Int) -> String {
            if length <= 0 {
                return self
            } else if let to = self.index(self.startIndex, offsetBy: length, limitedBy: self.endIndex) {
                return self.substring(from: to)

            } else {
                return ""
            }
        }
}

Swift - Remove character from string

Swift uses backslash to escape double quotes. Here is the list of escaped special characters in Swift:

• \0 (null character)
• \\ (backslash)
• \t (horizontal tab)
• \n (line feed)
• \r (carriage return)
• \" (double quote)
• \' (single quote)

This should work:

text2 = text2.replacingOccurrences(of: "\\", with: "", options: NSString.CompareOptions.literal, range: nil)

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