Explanation of Swift4.0 Array and explanation of swift4.0array

Source: Internet
Author: User

Explanation of Swift4.0 Array and explanation of swift4.0array

  • Array Introduction

An Array is a string of ordered elements of the same type. The set elements in an Array are ordered and can be repeated. In Swift, the Array type is Array, which is a generic set. Arrays are divided into variable arrays and immutable arrays. let-modified arrays are immutable arrays, and var-modified arrays are variable arrays.

  • Array Initialization

1. Initialize an empty array (type: [data type] ()

1. Create an empty array with an integer

Let array = [Int] ()

Here, the array variables are let's rhetoric. The array is an unchangeable array and can only be accessed and cannot be modified.

Var array = [Int] ()

Here, the array variable is called var. The array is a variable array and can be modified dynamically.

2. Create Any array that can store Any type [Any] ()

  • Use of Arrays
// Create a variable Array (which can store Any type of data) var arr: Array = [Any] () // create a variable Array (which stores the string type) // var arr1: [String] = [String] () // 1 Add the element appped () to the array // 1.1 add an element arr to the array. append ("xiaoming") print ("arr = \ (arr)") arr. append (1) print ("arr = \ (arr)"); // 1.2 add an Array to the Array let addArr: Array =, "tianjia"] as [Any] arr. append (addArr) print ("addArr = \ (arr)") // 1.3 Use the addition assignment operator (+ =) you can also add elements directly behind the array, but the added elements must be arrays in the form of the + = Operator, the right must be an array, even if there is only one element To be an array, in this way, you can add multiple values to the array at a time. let addArr1 = [6, 5] as [Any] arr + = addArr1 print ("arr = \ (arr )") // 1.4 Insert the arr element into the array. insert ("inserted element", at: 1) // 2. remove the element from the array // 2.1 remove the specific element arr. remove (at: 0) print ("removeArr = \ (arr)") // 2.2 remove all elements of the array arr. the removeAll () // removeAll method accepts a parameter that allows you to retain the array capacity when clearing the array. The default value of this parameter is false, which sets the capacity of the array to 0. If you want to maintain the capacity, refer to the following code: // var originalCapacity = arr. capacity // originalCapacity = 12 // arr. removeAll (keepingCapacity: true) // var newCapacity = arr. capacity // newCapacity = 12 // The code above shows that emptyArray can store 12 values before the memory needs to be re-allocated. However, with removeAll (), newCapcity is equal to 0. // 2.3 remove the first element of the array // arr. removeFirst () // 2.4 remove the last element of the array // arr. removeLast () // in these removal methods, the removed data is returned. // 3. array length let count = arr. count print ("arrCont = \ (count)") // 4. modify arr [1] = "xiugai" print ("xiuGai = \ (arr)") // 5. access the element let item = arr [1] print ("item = \ (item)") in the array )")

 

  • Traverse Arrays
Var stringArr: [String] = ["xiaoming", "tianya", "xiaoming ", "tiantian"] // traverses the array for item in stringArr {print ("iteem ==\ (item)")} for item in 0 .. <stringArr. count {print ("iteem ==\ (item)")} // set the traversal interval for item in stringArr [0... 2] {print ("iteem ==\ (item )")}

 

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.