如何使用Lua 优雅并快速的读取一个文件的全部内容？

在这里我们可以看一下代码:

local open = io.open
local insert = table.insert
local concat = table.concat

function load_file(filename)
    local file = open(filename, 'rb')
    if not file then
        return
    end
    local f = {}
    for line in file:lines("l") do
        insert(f, line)
    end
    file:close()
    return concat(f, '\n')
end

print('file size = ', #load_file('filename'))

这里使用time命令行工具进行5次读取计时:

bogon:~ candy$ time lua main.lua 
file size =     5570813

real    0m0.052s
user    0m0.037s
sys    0m0.013s
bogon:~ candy$ time lua main.lua 
file size =     5570813

real    0m0.051s
user    0m0.037s
sys    0m0.012s
bogon:~ candy$ time lua main.lua 
file size =     5570813

real    0m0.052s
user    0m0.037s
sys    0m0.012s
bogon:~ candy$ time lua main.lua 
file size =     5570813

real    0m0.054s
user    0m0.038s
sys    0m0.014s
bogon:~ candy$ time lua main.lua 
file size =     5570813

real    0m0.052s
user    0m0.037s
sys    0m0.012s
bogon:~ candy$