variables in echo or print

when or when do you not have to use a '. to call varialbe in echo or print

i have seen this


echo "hey hi heya".$var." bah ";

as well as

print "hey hi heya $var bah";

when do you have to quote period and when not

 

With just regular variables in double-quoted strings, there's not really any context where you need to use the concatenation operator ".".

You do, however, need to concatenate "." when calling functions, doing arithmetic, etc, and always in single-quotes.

For example:

// All of the following work
// For better readability, you may want to try wrapping your variables in brackets {}
// Regular variable
print "Hello, $name";
print "Hello, {$name}";
print "Hello, " . $name;

// Array variable
print "Hello, $person['name']";
print "Hello, {$person['name']}";
print "Hello, " . $person['name'];

// Object variable
print "Hello, $person->name";
print "Hello, {$person->name}";
print "Hello, " . $person->name;

// This does not work, because it is a single-quoted string
print 'Hello, $person';
// So you should use the concatenation operator in this case
print 'Hello, ' . $person;

// This also does not work, because you're calling a function
print "Hello, function()";
// So concatenate in this case as well
print "Hello, " . function();

PHP:

The ability to replace variables in strings is definitely a very useful convenience feature of PHP.

For more detailed information, you should consult the following page (specifically the variable parsing section):
http://us3.php.net/manual/en/language.types.string.php

 

Be careful. Single Quote and Double Quoes mean a different thing. You were asking when so you use '. , but then you ask about ". Single does not phrase the variables and a Double parases the variables.

 

use single quotes for strings since they are much faster