为什么我的Lua表在使用while循环时出错

Question

这是我的错误

Expected objects to be the same.
Passed in:
(table) {
  [1] = 1
  [2] = 2
  [3] = 3
  [4] = 4 }
Expected:
(nil)

这是我的代码，请有人可以帮助我

local function between(a, b)
  local table = {}
  while not a == 5 do
    local a = 1
    table[a] = a
    local a = a + 1
  end
  print(table)
end

return between

我尝试过使用 for 循环有人可以帮助我吗

Answer 1

该循环有几个问题需要修复才能使其正常工作：

local function between(a, b)
  local table = {}
  while a > 0 do
    -- local a = 1 -- this is not needed, as it:
    -- (1) creates a *new* `a` value, which shadows the original value without changing it
    -- (2) is reset every loop iteration without any impact on the `a` value above
    table[a] = a
    -- local a = a + 1 -- this creates yet another `a` variable that is only visible
    -- inside the loop, so doesn't have any impact on the `while` condition

    -- since you already have the number of iterations you want to do (`a`)
    -- you can simply keep subtracting from it until it reaches 0:
    a = a - 1
  end
  -- it's better to return the value, as you may do something other than printing
  return table
end

这应该可行，但在这些情况下，当您知道迭代次数时，最好使用循环for而不是while循环，因为它负责增加/减少循环变量：

local tbl = {}
for i = 1, a do tbl[i] = i end
return tbl

你应该避免使用table作为变量名，因为它与 Lua 已经提供的表值冲突。