Php accesses and modifies string characters like Arrays

The character in the string in PHP can be searched and modified by a string starting with 0 and containing numbers in square brackets similar to the array structure,

The character in the string in PHP can be searched and modified by a string starting with 0 and containing numbers in square brackets similar to the array structure,

For example, if you get the second $ str [1] or $ str {1}, {} is not recommended. It is best to use [].
The test is as follows:

The Code is as follows:

// Obtain the last character
$ Str = 'phpddt. com ';
Echo $ str [strlen ($ str)-1]; // m
// Modify the first character
$ Str = 'phpddt. com ';
$ Str [0] = 'a'; // ahpddt.com
// If the number in square brackets is out of the range, it will be blank.
$ Str = 'phpddt. com ';
$ Str [100] = 'y'; // phpddt.com y
// If the non-integer type is converted to an integer
$ Str = 'phpddt. com ';
$ Str ['a'] = 'y'; // phpddt.com y
$ Str = 'phpddt. com ';
$ Str [-1] = 'y'; // an error occurs when the negative number is: Warning: Illegal string offset:-1.

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