parse（Float64，trip）-错误：无法将行程解析为Float64

Question

The code that I use:

for trip in df[:Polyline]
      trip ＝ parse(Float64,trip)  |＞ eval
end

The error I get:

error:cannot parse trip as Float64

trip is a string like [[-8.764913,6.461675],[7.461345,9.754319]]

Answer 1

You did not provide a minimal working example in your question (try to edit it!). However this is what I understand that you need.

Suppose you have a String :

trip = "[[-8.7,6.4],[7.4,9.7],[3.4,2.1]]"

Use JSON.jl package to parse it:

julia> using JSON

julia> JSON.parse(trip)
3-element Array{Any,1}:
 Any[-8.7, 6.4]
 Any[7.4, 9.7]
 Any[3.4, 2.1]

You might prefer to have an Array of Float64 s instead:

julia> Vector{Float64}.(JSON.parse(trip))
3-element Array{Array{Float64,1},1}:
 [-8.7, 6.4]
 [7.4, 9.7]
 [3.4, 2.1]