Php array sorting methods

Array sorting method
There are two types:
1. Internal (memory) sorting
2. External sorting (large data volume, insufficient memory, external
Storage)

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Sorting is a basic skill for programmers.
I. Internal sorting
(1) exchange sorting
1. Bubble method

By default, the array is passed as a value instead of an address.
The object type will be discussed later. The default transfer of an object is Address transfer.

// Optimization: encapsulate the bubble sorting method into a function for future use

The code is as follows:	Copy code
Function bubbleSort (& $ myarr ){ $ Temp = 0; // defines an intermediate variable. // Outer Loop For ($ I = 0; $ I <count ($ myarr)-1; $ I ++ ){ For ($ j = 0; $ j <count ($ myarr)-1-$ I; $ J ++ ){ If ($ myarr [$ j]> $ myarr [$ j + 1]) { $ Temp = $ myarr [$ j]; $ Myarr [$ j] = $ Myarr [$ j + 1]; $ Myarr [$ j + 1] = $ Temp; } } } } $ Arry = array ); BubbleSort ($ arry ); Print_r ($ arry );

2. Quick sorting (magical fast, involving recursion)

3. Select sorting method

The code is as follows:

Copy code

Function selectSort (& $ myarr ){ $ Temp = 0; For ($ I = 0; $ I <count ($ myarr)-1; $ I ++ ){ // Assume $ I is the smallest number. $ Minval = $ myarr [$ I]; // Record the subscript of the minimum number I think $ MinIndex = $ I; For ($ j = $ I + 1; $ j <count ($ myarr); $ j + + ){ // Describe the minimum value, not the minimum value. If ($ minval> $ myarr [$ j]) { $ Minval = $ myarr [$ j]; $ MinIndex = $ j; } } // Final exchange $ Temp = $ myarr [$ I]; $ Myarr [$ I] = $ myarr [$ minIndex]; $ Myarr [$ minIndex] = $ temp; } }

4. Insert sorting method

Query speed: Bubble sort <select sort <insert sort

What I like most is exchange sorting, that is, bubble sorting. This method is easy to use, but not suitable for sorting large data volumes.