PHP loop through array with name

PHP loop through array with name

How can i loop through an array like this and retrieve the id and echo it
to the screen? Also how can i do a loop and find the one with the highest
id?
Im not a beginner i just have never really used arrays.
Array
(
[articles] => Array
(
[0] => Array
(
[id] => 650
)
[1] => Array
(
[id] => 649
)
[2] => Array
(
[id] => 645
)
[3] => Array
(
[id] => 399
)
);
Thanks in advanced.