PHP leaves the array reference problem after the Foreach loop

eg

Result

Explain:

1.foreach is not a block-level field, array reference ends, $k, $a does not free memory

2. When the first reference loop ends, the $a points to the last element of the array 4

3. When the second start loop (at which point $a is already pointing to the last element, is the reference)

The variation of the cyclic 4-time array is:

1-> [1,2,3,4]

2-> [1,2,3,4]

3-> [1,2,3,3] The third value points to the last element 3 but value is the global reference when the last loop points to the final element so value=3 also changes the value of the last element to 3.

4-> [1,2,3,3]

Precautions:

The 1.foreach implementation principle has an internal pointer concept

2.& 's foreach Loop end pointer points to the last element

How to avoid:

After using &foreach cycle unset ($a)