A collection of arrays of the first knowledge of Swift collection

Array Collection

Basic operations:

Array Collection definition: A collection of elements of the same type that are ordered by a sequence

Basic declaration of an array:

1, var strudentlist:array<int>; Declares a strudentlist array, the type of the array element is int

2, var strudentlist: [Int]; A lazy strudent list array declaration, array element type int type

Initialization of the array

1, var strudentlist:array<int>= [10,10,10]//Declaration initialization Studentlist Type

2, var strudentlist = [10,101]//According to the type inference ability of swift language to declare an array of studentlist, array element type is Int type.

3, var strudentlist = array<int> ()//Declare a null value of the strudentlist array, the type of the array element is INT type

4, var strudentlist = [String] ()//Declare a controlled strudentlist array, array element type is String type

We can use the two keyword Var and let when declaring an array, and when using Var, the value of the array can be changed later in the program, and the array cannot be changed after it has been declared.

Array element manipulation: Add, delete, change, insert Element

add element

Example: var strudentlist:array<string> = ["Zhang San", "Jack"];

1. Add an element at the end of the array

Strudentlist.append ("10 Yuan");

2. Add multiple elements at the end of the array

Strudentlist + = ["Mark", "R"];

inserting elements

Strudentlist.insert ("Flying Fish", atindex:num)//num is the position of the array to be inserted, note here that the position of the array is calculated from zero, such as [10,10] then his next table technique is 0,1

Delete Element

Let Names=strudentlist.removeatindex (num); NUM is the following table to delete the array elements, using this method of deletion, the method can return the contents of the deleted element, and if this element is not required we can directly strudentlist.removeatindex (num)

Traversal of an array

Array traversal AH there are three ways to use

1. For in output array element

For item in Studentlist {println (item); }

2. Output array subscript and element

For (ID, name) in enumerate (studentlist) {if (id! = studentlist.count-1) {print ("Item \ (ID): \ (name),")        ;        }else{println ("Item \ (ID): \ (name)"); }    }

3. Use this method to output

for (var i:int = 0; i < strudentlist.count-1; i++) {if (i! = strudentlist.count-2) {print ("Item \ (i): \ (St    Rudentlist[i]), ");    }else{println ("Item \ (i): \ (Strudentlist[i])"); }}

This article is from the "10 Yuan" blog, please be sure to keep this source http://tenyuan.blog.51cto.com/9401521/1620718

A collection of arrays of the first knowledge of Swift collection