PHP: string indexing

Question

What is the difference between $str[n] and $str{n}, given that $str is a string.

I noticed that both seem to work the same, except that {} does not occur in any documentation I found.

I found it in the string documentation: "Note: Strings may also be accessed using braces, as in $str{42}, for the same purpose." (but as stated in the answers, the [] syntax is a better pick) — Gras Double
– Gras Double, Commented Apr 12, 2017 at 7:27
The topic is also discussed on this question: Getting the first character of a string with $str[0]. — Gras Double
– Gras Double, Commented Apr 12, 2017 at 7:35

Your Common Sense · Accepted Answer · 2022-05-12 16:28:59Z

41

They are the same. However, they are getting rid of the {} syntax, so you should go with [].

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. The functions substr() and substr_replace() can be used when you want to extract or replace more than 1 character.

Note: As of PHP 7.1.0, negative string offsets are also supported. These specify the offset from the end of the string. Formerly, negative offsets emitted E_NOTICE for reading (yielding an empty string) and E_WARNING for writing (leaving the string untouched).

Note: Prior to PHP 8.0.0, strings could also be accessed using braces, as in $str{42}, for the same purpose. This curly brace syntax was deprecated as of PHP 7.4.0 and no longer supported as of PHP 8.0.0.

edited May 12, 2022 at 16:28

Your Common Sense

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answered May 19, 2009 at 22:00

Paolo Bergantino

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1 Comment

Kekoa Over a year ago

The braces {} are legacy from Perl hashes, and are being abandoned.

Your Common Sense · Accepted Answer · 2022-05-12 16:27:29Z

16

Be careful, $str[n] and $str{n} give n-th Byte of String, not n-th character of String. For multibyte encoding (UTF-8, etc.) one character doesn't need to be one Byte.

$str[0] – first Byte of string

mb_substr($str, 0, 1) – first character of string (including multibyte charsets)

http://php.net/mb_substr

edited May 12, 2022 at 16:27

Your Common Sense

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answered Jan 28, 2013 at 16:28

Patrik

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Mark Fox Over a year ago

It's worth noting that before PHP 5.6 the default encoding of the mbstring module is not UTF-8 — this can be changed in two places: within php scripts mb_internal_encoding('UTF-8'); -or- php.ini mbstring.internal_encoding='UTF-8'

baszach · Accepted Answer · 2022-05-12 16:23:27Z

2

I know this is an older question but I have to say that it is really important to understand that $str[n] is not returning the n-th char but the n-th byte. I just spent a whole day with this issue. There was a name $name = "Ömar" and the code retrieved the first letter with $name[0] which caused an error because of a malformed UTF-8 character (because "Ö", "Ä" etc need more than one byte)

TL;DR don't use indexing to retrieve chars from a string in PHP

answered May 12, 2022 at 16:23

baszach

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2 Comments

Your Common Sense Over a year ago

The answer immediately above yours: "Be careful, $str[n] and $str{n} give n-th Byte of String, not n-th character of String."

baszach Over a year ago

I know, but I just wanted to give some insight as to which errors could be caused by that. Maybe someone encounters a "Malformed UTF-8" error and will be happy to find my answer :)

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