Can you append strings to variables in PHP? [duplicate]

This is because PHP uses the period character . for string concatenation, not the plus character +. Therefore to append to a string you want to use the .= operator:

for ($i=1;$i<=100;$i++){    $selectBox .= '<option value="' . $i . '">' . $i . '</option>';}$selectBox .= '</select>';

In PHP use .= to append strings, and not +=.

Why does this output 0? [...] Does PHP not like += with strings?

+= is an arithmetic operator to add a number to another number. Using that operator with strings leads to an automatic type conversion. In the OP's case the strings have been converted to integers of the value 0.

More about operators in PHP:

• Reference - What does this symbol mean in PHP?
• PHP Manual – Operators

PHP syntax is little different in case of concatenation from JavaScript.Instead of (+) plus a (.) period is used for string concatenation.

<?php$selectBox = '<select name="number">';for ($i=1;$i<=100;$i++){    $selectBox += '<option value="' . $i . '">' . $i . '</option>'; // <-- (Wrong) Replace + with .    $selectBox .= '<option value="' . $i . '">' . $i . '</option>'; // <-- (Correct) Here + is replaced .}$selectBox += '</select>'; // <-- (Wrong) Replace + with .$selectBox .= '</select>'; // <-- (Correct) Here + is replaced .echo $selectBox;?>