对于每个数组修改[重复]

I have this following code:

foreach ($animals as $animal) {
    $animal = getOffSpring($animal);
}

Since I am setting $animal to a new string, will I be modifying the array as well please?

My run suggests that my array remains the same, but I want it to be modified with the new value. Is this the bug?

In other words, I want all the animals within my array to be modified to their offsprings

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You can use a reference:

foreach ($animals as &$animal) {
    $animal = getOffSpring($animal);
}
unset($animal);

The unset after the loop clears the reference. Otherwise you keep a reference to the last array element in $animal after the loop which will cause annoying problems if you forget about this and then use $animal later for something else.

Another option would be using the key to replace it:

foreach ($animals as $key => $animal) {
    $animals[$key] = getOffSpring($animal);
}

I think you are trying to do that.
When you take $animal variable and pass it to a function or modifie it inside foreach loop, you work with independent variable, that isn't linked to $animals array in any way ( if you don't link it yourself ), therefore all changes applied to it, don't result in modification of $animals array.

foreach ( $animals as $i => $animal )
{
    $animals[ $i ] = getOffSpring( $animal );
}

As @AlecTMH mentioned in his comment, array_map is also a solution.

array_map( 'getOffSpring', $animals );

You can use a reference to the value in the array

foreach ($animals as &$animal) {
    $animal = getOffSpring($animal);
}