以下代码将字符串数组转换为 float 数组:

a = ["4", "5.5", "6"]
a.collect do |value| 
  value.to_f 
end
=> [4.0, 5.5, 6.0]

为什么下面返回的是字符串数组而不是 float ？

b =  [ ["0.0034", "-0.0244", "0.0213", "-0.099"], 
       ["0.0947", "-0.1231", "-0.1363", "0.0501"], 
       ["-0.0368", "-0.1769", "-0.0327", "-0.113"], 
       ["0.0936", "-0.0987", "-0.0971", "0.1156"], 
       ["0.0029", "-0.1109", "-0.1226", "-0.0133"] ]

b.each do |row| 
    row.collect do |value|
        value.to_f
    end
end
=> [["0.0034", "-0.0244", "0.0213", "-0.099"], ["0.0947", "-0.1231", "-0.1363", "0.0501"], ["-0.0368", "-0.1769", "-0.0327", "-0.113"], ["0.0936", "-0.0987", "-0.0971", "0.1156"], ["0.0029", "-0.1109", "-0.1226", "-0.0133"]]

此外，有没有更好的方法来做到这一点？

最佳答案

因为您是在 b 上调用 each 而不是 collect，所以您最终会返回原始数组而不是新创建的数组。这是正确的代码(我更喜欢收集 map ，但那只是我):

b.map{ |arr| arr.map{ |v| v.to_f } }

https://stackoverflow.com/questions/9677868/