I have question because i think i doing unnecessary job.
e.g.
$phone = "222-333-444"
echo "Phone number is " . $phone;
$phone['2'] = "222-333-444"
echo "Phone number is " . $phone['2'];
Please explain is there ANY ANY ANY reason to do it the way above rather than"
$phone = "222-333-444"
echo "Phone number is $phone";
$phone['2'] = "222-333-444"
echo "Phone number is $phone['2']";
Both are right ways to print a variable. There's no right or wrong, just different approaches.
No, actually both are equivalent. I personally always write this, because for me it is far more explicit:
echo "Phone number is " . $phone['2'];
The only reason would be consistency and clarity. Concatenation is faster than interpolation, but the difference is so negligible it should not define your choice. I prefer the second personally.
No, there is not difference.
second example should be like this:
$phone = "222-333-444"
echo "Phone number is {$phone}";
$phone['2'] = "222-333-444"
echo "Phone number is {$phone['2']}";
{} are only necessary when the variable is an array and you want to specify an index. For plain variables, {} are optional.
{} notation is always better to prevent mistakes.
echo "this is".constant("CONSTANT"); or echo "this is ".CONSTANT; php.net/manual/en/function.constant.phpNo, there is no reason at all, unless your variable is an array and you need to access a specific index.
echo "Phone number is {$phone['2']}";