php - PHP中是否有类似NEGATIVE_INFINITY的东西？

Question

我喜欢 javascript 中的负无穷大值，我认为在很多情况下使用它是有用且干净的，但在 PHP 中找不到类似的东西，它存在吗？

Answer 1

-INF 

从 PHP Documentation 的评论中得到它:

I just learnt of INF today and found out that it can be used in comparisons:

echo 5000 < INF ? 'yes' : 'no';       // outputs 'yes'
echo INF < INF ? 'yes' : 'no';        // outputs 'no'
echo INF <= INF ? 'yes' : 'no';       // outputs 'yes'
echo INF == INF ? 'yes' : 'no';       // outputs 'yes'

You can also take its negative:

echo -INF < -5000 ? 'yes' : 'no';    // outputs 'yes'

Division by INF is allowed:

echo 1/INF;    // outputs '0'

And test for it:

is_infinite(INF);   returns true
is_infinite(-INF);  returns true
is_infinite(1.01);  return false