Solved: How do I check if a string contains another string

Absolutely, let’s get started with an introduction to the topic and then go in depth with our problem solution, explanation, and related themes.

Working with text programming languages is fundamental and especially in Swift, a powerful and intuitive language developed by Apple. A common task while working with strings is finding out whether a string contains another string. Swift makes it super easy to check and this functionality can be crucial in a number of scenarios like validation checks, searches, categorizing data and a lot more.

Let’s dive into the heart of this matter, learning how to tackle this problem with a practical approach.

Finding a String within a String in Swift

Swift provides built-in capabilities to easily handle this. The method we will be using is the contains method that Swift has for Strings.

let mainString = "Swift programming language"
let searchString = "program"
let containsWord = mainString.contains(searchString)

The code above will return true because the word “program” is indeed part of the “mainString”. The contains function is case-sensitive, which means it will consider “program” and “Program” as different strings. If you want to perform a case-insensitive check, you can convert both strings to the same case.

Step-by-step Explanation of the Swift Code

Let’s breakdown the above code to understand better:

  • We initialize two string variables: “mainString”, which will be our text to search within, and “searchString”, which is the text we are searching for.
  • We then use the contains method on our mainString and pass in our searchString as the parameter. This function checks if the searchString exists in the mainString and returns a boolean value.
  • This boolean value is stored in the containsWord variable. If the searchString is found within the mainString, true is returned else false is returned.
  • Finally, the print function is used to display the output in the console.

Swift String Libraries and Functions

Swift provides a robust set of String libraries and functions. These functions are methods built into the String structure. They are what you call on a string to perform operations that can manipulate Swift strings. Apart from contains, some other commonly used functions are count, isEmpty, append, insert etc.

This simple operation can be used in a variety of ways. Input validation is one of the key places where this can prove to be quite useful. Suppose you want to only proceed if a string contains a certain keyword, this contains function comes in quite handy in such scenarios.

Moreover, one needs to be aware of certain things while using the contains method. The method is case-sensitive, which can be a hurdle in some cases. We can overcome this by converting our strings while checking. Swift provides the lowercased and uppercased functions just for this.

With this information at your disposal, you now have the power to check if one string contains another using Swift. Happy coding!

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