What is the difference between echo (), print (), Print_r ()? _php Tips

ECHO is a PHP statement, print and Print_r are functions, statements have no return value, and functions can have return values (even if they are not used)
Print only prints out the values of simple type variables (such as int,string)
Print_r can print out the values of complex type variables (such as arrays, objects)

echo--output one or more strings
Description
void Echo (String arg1 [, String ...])//return value is NULL
echo "Hello", "friend";


Print--Output a string
Description
int print (string arg)//return value is cosmetic
print "Hello friend";

You can do these things
$name =print "Nihao \";
$STR = ' Test print value is $name. ';
Eval ("$print =\" $str \ ";");
Echo $print;

Print_r--Print easy to understand information about variables.
BOOL Print_r (mixed expression [, bool return])//Returns the value is Boolean, the parameter is a mix type, can be a string, shaping, array, object class Print_r () to display information about a variable easily understandable. If a string, integer, or float is given, the variable value itself is printed. If you give an array, the keys and elements will be displayed in a certain format. object is similar to an array.
Print_r () Moves the pointer to the last edge of the array.
You can
Print_r (str);
Print_r (int);
Print_r (array);
Print_r (obj);
You can also use Var_dump Var_export