tic
for i = 1:500
    data = textread('test.txt','%f','delimiter','\n');
end
toc
data(1)

start_time = time_ns()
for i = 1:500
    global data
    open("test.txt", "r") do f
        lines = readlines(f)
        data = parse.(Float64, lines)
    end
end
@printf("耗时: %.2f seconds\n", (time_ns() - start_time) / 1e9)
data[1]