You have all explained on this link, there you have a lot of examples that will show you everything.
Basicly it is a function that split sentence (any string) into array of words (string), but you need to send a request how to split that sentence.
"What + are + you + doing?"
For split u use: " + ";
You will get array like this:
Position 0 = "What";
Position 1 = "are";
Position 2 = "you";
Position 3 = "doing?";
Array start from 0 if you wonder what it is position 0.
Explode() is a construct developed for the lemmings game, it makes the lemming explode to blow a hole through the wall or floor
similarly float() is a construct developed for the lemmings game, it makes the lemming move slowly down,
The PHP function explode lets you take a string and blow it up into smaller pieces. For example, if you had a sentence you could ask explode to use the sentence's spaces " " as dynamite and it would blow up the sentence into separate words, which would be stored in an array. The sentence "Hello, I would like to lose weight." would look like this after explode got done with it:
The dynamite (the space character) disappears, but the other stuff remains, but in pieces. With that abstract picture of the explode function in mind, lets take a look at how it really works.
The explode Function
The first argument that explode takes is the delimiter (our dynamite) which is used to blow up the second argument, the original string. explode returns an array of string pieces from the original and they are numbered in order, starting from 0. Lets take a phone number in the form ###-###-#### and use a hyphen "-" as our dynamite to split the string into three separate chunks.