To filter an array in Swift: For instance, let’s filter an array of words such that only words less than 4 characters long remain: Output: This is the quick answer. But to know how filtering really works in Swift, please read along. How to Filter an Array in Swift In the introduction, you saw a […]
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You can use a final class in Swift to disable the inheritance of the class. For example, let’s create a class Student and make it a final class to disallow inheritance: If you now try to subclass this class, you are going to see a compile-time error: Output: This error says it is not possible
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A completion handler in Swift is a function that calls back when a task completes. This is why it is also called a callback function. A callback function is passed as an argument into another function. When this function completes running a task, it executes the callback function. Example Here is a demonstrative (but not
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To read the last line of a file in Python without storing the entire file in memory: Here is an example: The Naive Approach The most naive approach to read the last line of a file in Python is: Here is the code: Find the Last Line of a Large File in Python If you
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To check if a Swift array contains an object with a specific property: For instance, let’s find out if a student called Bob is in an array of students: To understand how this works and to get the context, please read along. Full Example with Context First of all, let’s give context to the above
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To get the current time in Swift: For example, let’s show what time it is right now in the console: Output: A Deeper Dive Let’s take a closer look at the above Swift code. This Swift code imports the Foundation framework, which provides fundamental data types, collections, and operating-system services to the Swift programming language.
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To calculate the time difference between two Date objects in seconds in Swift, use the Date.timeIntervalSinceReferenceDate method. For example, let’s calculate how many seconds is between Christmas and New Year: Output: Date Difference Extension in Swift If you need to compute time differences between two dates more often in your project, feel free to write
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In Swift, looping with an index is a common technique used to iterate through a collection of items and perform some operation on each item. This technique is useful when you need to access individual elements in the collection, modify them, or perform some calculations based on their position. By using a loop with an
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To get the first index of an item in an array in Swift, use the array.firstIndex(where:) method. For instance, let’s find the first occurrence of the string “a” in an array: Output: Don’t let the $0 notation confuse you. Here is how it works: If you are still confused about the $0 notation, feel free
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In Python, the assert statements make sure a condition is met before continuing the execution of the program. For example, let’s assert that a discounted price does not go below 0 nor surpass the original price: Calling this function with an input that makes the assertion fail will lead to the code crash with a
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