echo 'Testing ' . 1 + 2 . '45';

Simply you will give the answer as : Testing 345

But the answer is : 245

That is because you can not sum a number with a string. The first part, before the plus mark is a string though there is 1 there.
So engine will simply get it as 0 and the latter part as 245. so answer will be 245.

Which of the following will not combine strings $s1 and $s2 into a single string?


$s1 = 'a';
$s2 = 'b';
A. $s1 + $s2
B. "{$s1}{$s2}"
C. $s1.$s2
D. implode('', array($s1,$s2))
E. All of the above combine the strings

You can not concatenate 2 string using “+”. The answer will be “0″; so here the answer is A.

$alpha = 'abcdefghijklmnopqrstuvwxyz';
$letters = array(15, 7, 15);
foreach($letters as $val) {
/* What should be here */
}

A. echo chr($val);
B. echo asc($val);
C. echo substr($alpha, $val, 2);
D. echo $alpha{$val};
E. echo $alpha{$val+1}

An array can be accessed like this as well. $alpha{$val}

What will out put the following code snippet?

<?php
$who = "questions";
echo <<<TEXT
So I said, "php interview $who"
TEXT;
?>

Answer – So I said, “php interview questions”

In general, the functionality of this heredoc syntax is similar to double quotes.

“I am visiting the php interview questions website”.
The word “question” is inside a variable,
$a = ‘question’;

Answer is just,
echo “I am visiting the php interview {$a}s website”;

In a php interview, even a well experienced php programmer might forget how this works,
For an example,
a) echo “Hello $what\n”;
b) echo ‘Hello $what\n’;
$what = “World”;

Which will print correctly in to the browser as “Hello World” followed by a new line.
Is it a) or b) ?

The answer is “a”. That is because simple string will print almost all characters literally, where complex string allows special escape sequences to insert special characters.