We look at the syntax for using Swift's built-in filter function, and then compare it with the traditional procedural way.
- [Instructor] The next important built-in array function…is called filter.…Filter is used when you want to extract…all of the elements in an array…that fit some kind of criteria.…For example, if we have an array of numbers…and we want to get all the numbers from it…that are even.…Or if we have an array of employee data…and we want to find the employees from this array…that make more than a certain amount per year.…These are things that filter can help us with.…The syntax of filter is similar to map.…We can call it on any array…and then we pass in a function.…The main difference between filter and map is the type…of function that we pass into it.…
In map, we pass in a function that returns a value…for each element in an array.…The return value of this function represents…what an element becomes in our new array.…On the other hand for filter,…we pass in a function…that returns either true or false for each element.…If the function that we pass returns true…for a given element,…then the element is included in the final array.…
- What is functional programming?
- Keeping functions and data separate
- First-class functions
- Working with arrays functionally
- Filtering and reducing
- Partial-application and recursion
Skill Level Intermediate
Swift 4: Protocol-Oriented Programmingwith Károly Nyisztor1h 44m Intermediate
Swift: Delegations and Data Sourceswith Steven Lipton1h 6m Intermediate
Swift: Writing Reusable Frameworkswith David Okun1h 49m Intermediate
1. What Is Functional Programming?
2. First-Class Functions
3. Array Functions
4. Advanced Functional Concepts
Next steps1m 1s
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