Differences between echo, print and print_r in PHP

echo :
Outputs one or more strings. And echo is not a function, but a language construct. echo has a void return type.echo is not actually a function (it is a language construct), so you are not required to use parentheses with it. echo (unlike some other language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if you want to pass more than one parameter to echo, the parameters must not be enclosed within parentheses.
For example:
<?php   echo “Hello World”; ?>

echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. This short syntax only works with the short_open_tag configuration setting enabled.
For example:
My name is <?=$name; ?>.

Note: However, short tags are discouraged to use in modern versions on PHP..

print:
print is not actually a real function (it is a language construct) so you are not required to use parentheses with its argument list. print has a return value of 1 so it can be used in expressions.
For example:
<?php
print(“hello world!”);
print “hello world”;
?>

However, echo is slightly faster than print.

print_r():
It displays information about a variable in a way that’s readable by humans.
For example:
<pre>
<?php
$a = array (‘a’ => ‘apple’, ‘b’ => ‘banana’, ‘c’ => array (‘x’, ‘y’, ‘z’));
print_r ($a);
?>
</pre>