Get all data from RAM

It is just a theoretical question, which I'd like to ask:
 Is there a method to start reading memory addresses one by one and show it's values, even those are not belongs to my program?
Here is my stupid JS-like example (I'm not a programmer):

for (address in RAM) {
    console.log("RAM addr " + RAM[address] + " > " + RAM[address][value])
}
// output:
// ...
// RAM addr 0x347A2C10 > 0x00000002
// RAM addr 0x347A2C11 > 0x00000000
// ...
// RAM addr 0x347A2C20 > 0x0000FF25
// ...

Thanks to every answer! ;)

No. This would be a massive security problem. The OS will not allow you to read the entire content of the RAM.