$arr1 = array("php", "java", "c++", "python");
$arr2 = array("c#", "c", "javascript");
$arr3 = array("vb.net", "go", "typescript", "node.js");
$merge_array = array_merge($arr1, $arr2, $arr3);
print_r($merge_array);
/*
run:
Array
(
[0] => php
[1] => java
[2] => c++
[3] => python
[4] => c#
[5] => c
[6] => javascript
[7] => vb.net
[8] => go
[9] => typescript
[10] => node.js
)
*/