Practical Tips for javascript Array Operations _ javascript skills

The methods of arrays and string objects are very confusing. Therefore, you can list them so that you do not need to query them each time. 1. concat Method
[Function] concatenates multiple arrays. This method does not change the existing array. It only returns a copy of the combined array.
[Syntax] arrayObj. concat (array1, array2 ,...)
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2"); var array2 = new Array ("3", "4 "); var array3 = array1.concat (array2); document. write (array3 + ""); document. write (array3 [0]); script
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2. join method,
[Function] converts an existing array object into a string, which can be concatenated with a specified separator.
[Syntax] arrayObj. join (separator). The default Delimiter is ",".
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2"); document. write (array1.join (); script
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3. pop and shift Methods
[Function] The pop method deletes and returns the last element of the array. At the same time, the length of the array changes. In contrast to the shift () method, the first element of the array is deleted and returned.
[Syntax] arrayObj. pop | shift ()
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2", "3", "4"); document. write (array1.pop () + "<br>"); document. write (array1.length + "<br>"); document. write (array1.shift () + "<br>"); document. write (array1.length); script
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4. push and unshift Methods
[Function] adds one or more elements to the end of the array and returns a new length. At the same time, the length of the array will be changed, which corresponds to the unshift method. Note that the return value of the method is not a new array, but the length of the new array.
[Syntax] arrayObj. push | unshift (ele1, ele2, ele3 ,...)
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2", "3", "4 "); var newL = array1.push ("5", "6"); document. write (newL + "<br>"); document. write (array1); script
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5. reverse Method
[Function] reverses the order of elements in the array.
[Syntax] arrayObj. reverse ()
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2", "3", "4"); document. write (array1.reverse (); script
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6. slice Method
[Function] returns the elements selected from the existing array.
[Syntax] arrayObj. slice (startposition, endposition). The first parameter is required, and the second parameter is optional. If no value is specified, the default value is from startposition to the last element. Note that the element that contains the position startposition does not include the endposition.
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("1", "2", "3", "4"); document. write (array1.slice (0, 2); script
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7. sort Method
[Function] is used to sort array elements.
[Syntax] arrayObj. sort (sortRule ()). Optional. It indicates the sorting method. Note that sort sorting has several basic principles: first, sort by letter by default, and second, before lowercase letters. In order to sort numbers, you need to write the sorting method by yourself.
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("c", "a", "d", "B "); var array2 = new Array ("c", "a", "D", "B"); var array3 = new Array ("100", "2 ", "3", "1") function sortRule (a, B) {return a-B;} document. write (array1.sort () + "<br>"); document. write (array2.sort () + "<br>"); document. write (array3.sort (sortRule); script
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8. splice Method
[Function] deletes an array and adds new elements.
[Syntax] arrayObj. splice (index, number, ele1, ele2 ...). The index is the index position and must be a number, indicating the position from which the element is inserted or deleted. Number indicates the number of elements to be deleted from the index position. If it is set to "0", a new element is inserted to the index and the array elements to be deleted are not deleted. (Too mixed ~~~ Directly look at the code instance)
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("c", "a", "d", "B"); array1.splice (0, 0, "m") document. write (array1 + "<br>"); array1.splice (0, 2, "n") document. write (array1); script
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9. toString Method
[Function] The method with very high usage directly converts an array type object to a string type object.
[Syntax] arrayObj. toString ()
[Instance]

<Script type = "text/javascript"> var array1 = new Array ("c", "a", "d", "B"); strObj = array1.toString (); document. write (strObj + "<br>"); script
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Note: The new string is composed of the original array, but it is separated by commas (,). To remove the comma (,), you can write it as follows:

<Script type = "text/javascript"> var array1 = new Array ("c", "a", "d", "B"); strObj = array1.toString (). replace (/,/g, ""); document. write (strObj. replace + "<br>"); script
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