Array_column PHP functions

Today I want to take a column from a two-dimensional array into a one-dimensional array the results found that Array_column needed php5.5 support and wrote a copy of the Array_column.

Two ways of thinking

1. Direct traversal value to append array return

2. First, the two-dimensional array key is determined to traverse the key by the value of the append array returned

It turns out that the second method is much faster, and it's strange to assume that the index array traversal is faster;

Array_column PHP functions