Php traverses the array $ arr. what is the structure of the $ arr array below? how can I output the result of traversal? 123

Php traverses the array $ arr. what is the structure of the $ arr array below? how can I output the result of traversing the output: 123 using print_r ($ arr );
Output: Array ([0] => 1, 3, 2)
Use var_dump ($ arr );
Output: array (1) {[0] => string (5) "1, 3, 2 "}
For loop output to obtain
For ($ I = 0; $ I <sizeof ($ arr); $ I ++ ){
Echo $ arr [$ I];
}
Output: 1, 2, 3
// The comma actually traverses
What is the structure of this number? how can I remove the comma when traversing this for loop,
Only output the following structure:
1
2
3

Reply to discussion (solution)

$ Arr is an array $ arr = array ('1, 2, 3 ')
You CAN $ arr = explode (',', array ('1, 2, 3 '));
For loop again

Well, yes, thanks.