最简单的函数写法
julia> f(x) = 2x
f (generic function with 1 method)
julia> map(f, [2,4,6,8])
稍微简化一下的写法
map(x -> 2x, [2,4,6,8])
map(x->sqrt(abs(sin(x))), [1,2,3])
从Juliacn上面抄来的一个写法
split(string("a"^20,"b"^3,"c"^2),"")
println(s)
@time split(string("a"^20,"b"^3,"c"^2),"") |> x->[count(i->i==j, x) for j in unique(x)]
最头大的就是词典了，一直很难明白词典的使用方法
比如数一下一个字符串中重复个体的数量，返回一个词典
function dicUni(a)
u=unique(a)
d=Dict([(i, count(x->x==i,a)) for i in u])
end
println(dicUni(s))
Dict("c"=>2,"b"=>3,"a"=>20)
如果放在for loop里面，则是
function f(x)
t=[]
d=Dict()
for i in unique(x)
t1 = count(j -> j == i, x)
t = push!(t, t1)
d[i] = t1
end
return t,d
end
a,b=f(s)
println(b)
Dict{Any,Any}("c"=>2,"b"=>3,"a"=>20)
从词典变成dataframe
using DataFrames
x = collect(keys(b))
y = collect(values(b))
z = DataFrame([collect(keys(b)), collect(values(b))], [:A, :B])
