PHP将数组值转换为键

Question

Given the following array:

Array
(
    [0] => 'lorem ipsum'
    [1] => 'dolor sit amet'
    [2] => 'consectetur adipiscing elit'
)

What is the best way to convert this to the following:

Array
(
    ['lorem ipsum'] => true
    ['dolor sit amet'] => true
    ['consectetur adipiscing elit'] => true
)

Other than foreach-ing and creating a new array? Is there any built-in PHP function that can do this for me?

The values of the keys in the new array will always be a fixed value, i.e true.

I looked at array_flip but don't think this will allow me to apply a fixed value.

Answer 1

As AlivetoDie noted, there's no built in, single call method you could use. But if you simply want to omit foreach (and creating intermediary results), the following is a one-line solution:

$out = array_combine($in, array_fill(0, count($in), true));

https://3v4l.org/YFBkW

or:

$out = array_map(function () { return true; }, array_flip($in));

if you need more control.