如何将科学记数法字符串转换为十进制记数法?

问题描述

我想将 csv 文件中的所有科学记数法字符串find 和 convert 转换为十进制记数法，例如:

I'd like to find and convert all scientific notation strings in a csv file to decimal notation, e.g.:

1.0e-05 to 0.00001

我怎样才能在 ruby​​ 中做到这一点?

How can I do that in ruby?

推荐答案

只需使用字符串转换即可.浮动的必要强制将自动完成:

Just use string conversion. The necessary coercion to float will be done automatically:

"%f" % "1.0e-05"
=> "0.000010"

# Which, behind the scenes is the same as:
"%f" % "1.0e-05".to_f
=> "0.000010"

根据需要进行调整以获得或多或少的准确性.例如:

Adjust as necessary to get more or less accuracy. For example:

"%.5f" % "1.0e-05"
=> "0.00001"

如果您想获得真正的幻想并在最后去掉不必要的零，这是一种方法.(希望有人会建议更优雅的东西；我想不出任何东西):

If you want to get real fancy and chop off unnecessary zeros at the end, here's one way. (Hopefully someone will suggest something more elegant; I couldn't think of anything):

("%.20f" % "1.0e-05").sub(/\.?0*$/, "")
=> "0.00001"

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