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phpdynamic-typingweak-typing

A string in PHP that doesn't make sense

I was experimenting with weak/dynamic typing properties of PHP in preparation for a test and was completely baffled by the output of this string concatenation. Can someone explain how this is even possible?

<?php echo  1 . "/n" . '1' + 1 ?><br />

output:

2

Solution

  • Analysis:

    echo  1 . "/n" . '1' + 1;

    is equivalent to

    //joined first 3 items as string
echo "1/n1"+1;

    is equivalent to 

    //php faces '+' operator, it parses '1/n1' as number
//it stops parsing at '/n' because a number doesn't
//contain this character
echo "1"+1;

    is equivalent to 

    echo 1+1;