如何在StringBuilder中格式化Scala中的浮点数？

Question

晚上好，

我想在StringBuilder中格式化Scala中的浮点数。下面的代码有效，但很冗长。当然，有一种更简洁的方法可以做同样的事情。

谢谢。

var myDouble: Double = 1.23456789
val stringBuilder = StringBuilder.newBuilder
stringBuilder.append(s"My double: ${BigDecimal(myDouble).setScale(5, BigDecimal.RoundingMode.HALF_UP)}")
println(stringBuilder.toString())

Answer 1

这样的东西？

pip install pyparsing
Traceback (most recent call last):
  File "/usr/bin/pip", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 72, in <module>
    import packaging.requirements
  File "/usr/local/lib/python2.7/dist-packages/packaging/requirements.py", line 9, in <module>
    from pyparsing import stringStart, stringEnd, originalTextFor, ParseException
ImportError: No module named pyparsing