Differences between for and foreach in PHP _ PHP Tutorial

Source: Internet
Author: User
Differences between for and foreach in PHP. Note: Unless the array is referenced, foreach operates on a copy of the specified array, rather than the array itself. Therefore, the array pointer is not changed by the each () structure. Note to the returned array: unless the array is referenced, foreach operates on a copy of the specified array, rather than the array itself. Therefore, the array pointer is not changed by the each () structure, and the modification to the returned array unit does not affect the original array.

1. since php5, foreach may also traverse object attributes.
2. since php5, foreach can easily add & before $ value to modify the array unit. this method will assign values by reference instead of copying a value.

The code is as follows:


$ Arr = array (1, 2, 3, 4 );
Foreach ($ arr as & $ value ){
$ Value = $ value * 2;
}
?>
Output: $ arr = array (2, 4, 6, 8)


Note: foreach does not support "@" to suppress error messages.

Except that the array is referenced, foreach operates on a copy of the specified array, rather than the array itself. Therefore, the array pointer is not changed by the each () structure...

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