Similarities and differences between the two ways of merging two arrays

Two ways to merge arrays: $a + $b, array_merge ($a, $b)

Merging indexed arrays using the operator +, duplicate indexes are discarded, and duplicate indexes with Array_merge () are reset, as in the following scenario:

1php > $a =Array (); 2 3php > $b = Array (1='Data'); 4 5php > $c = $a +$b; 6 7php > $d =array_merge ($a, $b); 8 9php >var_dump ($c, $d); Ten  One //Output Results A  -Array1) {  [1] =string(4)"Data" }   -  theArray1) {  [0] =string(4)"Data"}

Therefore, when using + to merge two indexed arrays, the values may be discarded, and array_merge will not, resetting the duplicate index:

1php > $a = Array (1=' One',2=' Both',3='three'); 2php > $b = Array (3='three',4=' Four',5='Five'); 3php > $c = $a +$b; 4php > $d =array_merge ($a, $b); 5php >var_dump ($c, $d); 6Array5) {  7[1] =string(3)" One"  8[2] =string(3)" Both"  9[3] =string(5)"three"  Ten[4] =string(4)" Four"   One[5] =string(4)"Five"   A }   -  -Array6) {   the[0] =string(3)" One"   -[1] =string(3)" Both"   -[2] =string(5)"three"   -[3] =string(5)"three"   +[4] =string(4)" Four"   -[5] =string(4)"Five"   +}

Similarities and differences between the two ways of merging two arrays