Php deep Replication

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phpClass test {public $ num = 100;} $ a = new test (); $ B = clone $ a; $ a-> num = 200; echo $ B-> num; // 100 class test {public $ num = 100;} $ a = new test (); $ B = $ a; $ a-> num = 200; echo $ B-> num; // 200 // array $ a = [, 3]; $ B = $ a; $ a [1] = 5; var_dump ($ B); // [1, 2, 3] $ a = [1, 2]; $ B = & $ a; $ a [1] = 5; var_dump ($ B); // [, 3] // The above is the php deep copy, light copy, right?

Reply content:

phpClass test {public $ num = 100;} $ a = new test (); $ B = clone $ a; $ a-> num = 200; echo $ B-> num; // 100 class test {public $ num = 100;} $ a = new test (); $ B = $ a; $ a-> num = 200; echo $ B-> num; // 200 // array $ a = [, 3]; $ B = $ a; $ a [1] = 5; var_dump ($ B); // [1, 2, 3] $ a = [1, 2]; $ B = & $ a; $ a [1] = 5; var_dump ($ B); // [, 3] // The above is the php deep copy, light copy, right?

Class SubTest {public $ num = 100;} class Test {public $ child; function _ construct ($ child) {$ this-> child = $ child ;}} $ a = new Test (new SubTest (); // perform a shallow copy here $ B = clone $ a; $ B-> child-> num = 200; // The output below is 200 echo $ a-> child-> num, "\ n"; echo $ B-> child-> num, "\ n "; class Test2 {public $ child; function _ construct ($ child) {$ this-> child = $ child;} // this method is called when the clone is complete, complete the deep copy operation function _ clone () {$ this-> child = clone $ this-> child ;}}$ a = new Test2 (new SubTest () here ()); // perform deep copy here $ B = clone $ a; $ B-> child-> num = 200; // The output below is 100,200 echo $ a-> child-> num, "\ n"; echo $ B-> child-> num, "\ n ";

Reference PHP: Object Replication

The subject's Code contains copying and referencing two conceptual objects. See objects and references.

It is difficult to describe deep replication and light replication, and the Code on the upstairs also shows the difference. Two intuitive images are presented, so that we can better understand it.
Light Replication:

Deep Replication: