What is the difference between echo(), print(), print_r()? _PHP Tutorial

echo is a PHP statement, print and print_r are functions, statements have no return value, functions can have return values ​​(even if they are useless)
print can only print out the values ​​of simple type variables (such as int, string)
print_r can Print out the value of complex type variables (such as arrays, objects)

echo -- Output one or more strings
Description
void echo ( string arg1 [, string ...] ) / /The return value is empty
echo "Hello", "Friend";


print --output a string
Description
int print ( string arg )//return The value is an integer
print "Hello friend";

You can perform the following operations
$name=print "nihao n";
$str = 'test print value is $name .' ;
eval("$print="$str";");
echo $print;

print_r -- Print easy-to-understand information about the variable.
bool print_r (mixed expression [, bool return] ) //The return value is Boolean, the parameter is mix type, which can be string, integer, array, object class print_r() displays easy-to-understand information about a variable information. If a string, integer or float is given, the variable value itself will be printed. If an array is given, the keys and elements will be displayed in a certain format. object is similar to an array.
print_r() will move the array pointer to the end.
You can
print_r(str);
print_r(int);
print_r(array);
print_r(obj);
You can also use var_dump var_export

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