PHP ʖ²ἯTH º󍋼/A abs èʶ =ד 1. abs() $abs = abs(-4.2); // $abs = 4.2; (double/float) $abs2 = abs(5); // $abs2 = 5; (integer) $abs3 = abs(-5); // $abs3 = 5; (integer) º󍋼/A ưµ㼯A ʽѧº¯ʽ ɏһ¼¶ acos