JavaScript Advanced Programming (Third edition) Chapter fifth reference types

5.2 Array Type

1 var colors = new Array (3);      Create an array of 3 items with 2 var names = new Array ("Greg");  Create an array that contains 1 items, the string "Greg"

5.2.2 Conversion method

1 var colors = ["Red", "Blue", "green"];    Create an array containing 3 strings of 2alert (colors.tostring ());    Red,blue,green3alert (colors.valueof ());     Red,blue,green4 alert (colors);               Red,blue,green

1 var colors = ["Red", "green", "Blue"]; 2 Alert (Colors.join (","));      Red,green,blue3 alert (colors.join ("| |)");     red| | green| | Blue

5.2.3 Stack method

1 var colors = ["Red", "Blue"]; 2 Colors.push ("Brown");              Add another item 3colors[3] = "BLACK";               Add an item 4alert (colors.length);  45         6var item = Colors.pop ();           Get the last 7 alert (item);  "Black"

5.2.4 Queue method

1 var colors = new Array ();                      Create an array of 2var count = Colors.push ("Red", "green");       Push in two 3alert (count);  24         5count = Colors.push ("Black");                  Push into another 6alert (count);  37         8var item = Colors.shift ();                     Get the first 9 alert (colors.length);  2

5.2.5 re-ordering method

1 var values = [1, 2, 3, 4, 5]; 2 values.reverse (); 3 alert (values);       5,4,3,2,1

1 function Compare (value1, value2) {2if (value1<value2) {3 return 1;4 } else if (value1>value2) {5 return-1;6 } else {7 return 0;8     }9 }Ten  One var values = [0, 1, 5, ten, +]; A Values.sort (compare); -alert (values); 15,10,5,1,0

5.2.6 Method of operation

1 var colors = ["Red", "green", "Blue"]; 2 var colors2 = Colors.concat ("Yellow", ["Black", "Brown"]); 3 4 alert (colors);     Red,green,blue        5 alert (colors2);    Red,green,blue,yellow,black,brown

1 var colors = ["Red", "green", "blue", "yellow", "purple"); 2 var colors2 = colors.slice (1); 3 var colors3 = Colors.slice (1,4); 4         5 alert (colors2);   Green,blue,yellow,purple6 alert (COLORS3);   Green,blue,yellow

1 var colors = ["Red", "green", "Blue"];2 var removed = Colors.splice (0,1); Delete First item3 alert (colors); Green,blue4 alert (removed); Red, the returned array contains only one item5         6 removed = colors.splice (1, 0, "yellow", "orange"); Insert two items starting from position 17 alert (colors); Green,yellow,orange,blue8 alert (removed); An empty array is returned.9 Ten removed = Colors.splice (1, 1, "Red", "purple"); Insert two items to delete an item One alert (colors); Green,red,purple,orange,blue Aalert (removed); Yellow, the returned array contains only one item

5.2.7 Location method

1 var numbers = [1,2,3,4,5,4,3,2,1];2 3 Alert (Numbers.indexof (4)); 34 Alert (Numbers.lastindexof (4)); 55 6 Alert (Numbers.indexof (4, 4)); 57 Alert (Numbers.lastindexof (4, 4));//38 var person = {Name: "Nicholas"};9 var people = [{name: ' Nicholas '}];Ten var morepeople = [person]; One  A Alert (People.indexof (person)); -1 -Alert (Morepeople.indexof (person)); 0

5.2.8 Iterative method

• Every (): Runs the given function for each item in the array, and returns True if the function returns true for each item.
• Filter (): Each item in an array runs the given function, and returns a list of items that are true of the function.
• ForEach (): Runs the given function for each item in the array. This method has no return value.
• Map (): Each item in the array is a given function that returns an array of the results of each function call.
• Some (): Runs the given function for each item in the array, and returns True if the function returns true for either item.

1 var numbers = [1,2,3,4,5,4,3,2,1];2         3 var everyresult = numbers.every (function (item, index, array) {4 return (item > 2);5     });6         7 alert (Everyresult); False8         9 var someresult = numbers.some (function (item, index, array) {Ten return (item > 2); One     }); A          -alert (Someresult); True

 1  var numbers = [1,2,3,4,5,4,3,2,1];  2  var F Ilterresult = Numbers.filter (function (item, index, array) { 4   return (item > 2);  5  });    6  7  alert (filterresult); [3,4,5,4,3] 

1         var numbers = [1,2,3,4,5,4,3,2,1]; 2         3         var mapresult = numbers.map (function (item, index, array) {4            return item * 2; 5         }); 6         7         alert (mapresult);   [2,4,6,8,10,8,6,4,2]

JavaScript Advanced Programming (Third edition) Chapter fifth reference types