julia JSON.parse losing type information -
i started learn julia have issue:
i trying use julia's json.parse
parse matrix (a list of coordinates) losing type information.
coords = json.parse("[[1.0,-2.0],[3.0,4.0],[5.0,-1.2]]")
it returning any
type instead of float
type:
3-element array{any,1}: {1.0,-2.0} {3.0,4.0} {5.0,-1.2}
how (or convert this) array of floats?
edit. here larger problem:
taxi_df = readtable("./test.csv") coords = [json.parse(x) x in taxi_df[:polyline]] times = [float(length(x)*15) x in coords] df_submission = dataframe() df_submission[:trip_id] = taxi_df[:trip_id] mean_time = mean(times) df_submission[:travel_time] = [max(x, mean_time) x in times] writetable("submission.csv", df_submission)
i think doing in first place because data list-of-lists in json, can't convert matrix.
you can do
float(hcat(coords...))
if columns, or
float(hcat(coords...))'
if rows. if efficiency critical code, can preallocate output matrix , use loop, e.g.
a = zeros(3,2) in 1:3, j in 1:2 @inbounds a[i,j] = coords[i][j] end
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