对 table.sort 的比较函数的理解不到位,结果把我害惨了T T
Lua 5.1 手册里是这么写的:
table.sort (table [, comp])
Sorts table elements in a given order, in-place, from table[1] to table[n], where n is the length of the table. If comp is given, then it must be a function that receives two table elements, and returns true when the first is less than the second (so that not comp(a[i+1],a[i]) will be true after the sort). If comp is not given, then the standard Lua operator < is used instead.
The sort algorithm is not stable; that is, elements considered equal by the given order may have their relative positions changed by the sort.
文中说:returns true when the first is less than the second
那如果两个参数相等应该返回什么?false!
关键就是这个,必须返回 false,否则排序的结果不正确。