Consider
$foo = "abcdefg";
echo $foo[0]; //outputs a
So it seems like strings are like array of characters but then why
foreach($foo as $char)
{
echo $char;
}
does not work and gives following Warning ??
Warning: Invalid argument supplied for foreach()
Adding string iteration support to foreach was discussed but declined. There were mainly two reasons for this decision:
To solve both problems there was a proposal to introduce a TextIterator, which you pass a string and a charset. That way you can't accidentally iterate a string and the byte vs character problem doesn't exist. I'm not sure though what the state of the TextIterator is currently.
\X.
\X matches only extended unicode sequences (i.e. a non-mark character followed by an arbitrary number of mark-characters), whereas Perl goes all the way of matching extended grapheme clusters.NikiC's answer covers why doing this directly is not possible.
If you want to iterate over a string as if it were an array, you can be explicit by using str_split:
foreach(str_split($foo) as $char)
{
echo $char;
}
Warning: str_split is not encoding-aware, so you will end up iterating over bytes and not over characters. Iterating over characters is a little more involved, as there is no equivalent multibyte split function. You can roll your own using the regex-enabled mb_split, look at the comments from PHP.net for ideas.
There are other answers here suggesting you should cast the string to an array, but I don't understand why that would work. The documentation is pretty explicit:
For any of the types: integer, float, string, boolean and resource, converting a value to an array results in an array with a single element with index zero and the value of the scalar which was converted. In other words, (array)$scalarValue is exactly the same as array($scalarValue).
And indeed, doing this does not work as suggested.
Even though their characters can be addressed using square brackets, strings aren't arrays. Emphasis mine:
Characters within strings may be accessed and modified by specifying the zero-based offset of the desired character after the string using square array brackets, as in $str[42]. Think of a string as an array of characters for this purpose.
it is called "syntax sugar".
For example, in 5.4 you'll be able to do like this echo func()[0];
That doesn't mean that a function is really an array of charactes.
It's just a syntax.
echo $foo{0};I never understood why they changed it.