Converting 5.223701009526849e-05 to 5e-05
Ben Finney
ben+python at benfinney.id.au
Sun May 3 04:40:38 EDT 2015
Cecil Westerhof <Cecil at decebal.nl> writes:
> When I have a value like 5.223701009526849e-05 in most cases I am not
> interested in all the digest after the dot.
What type of value is it?
A ‘float’ value has many different textual representations, most of them
inaccurate. So talking about the digits of a ‘float’ value is only
partly meaningful; digits are a property of some chosen representation,
not intrinsic to the number.
A ‘str’ value can be converted in various ways, but is useless as a
number until you create a new number from the result.
Choosing a solution will rely on understanding that the textual
representation of a number is not itself a number; and vice versa, a
number value does not have a canonical text representation.
> Is there a simple way to convert it to a string like '5e-05'?
Assuming we're talking about a ‘float’ value::
>>> foo = 5.223701009526849e-05
>>> "{foo:5.1}".format(foo=foo)
'5e-05'
See the ‘str.format’ documentation, especially the detailed
documentation for the “format specification mini-language”
<URL:https://docs.python.org/3/library/string.html#format-specification-mini-language>
for how to specify exactly how you want values to be formatted as
text.
--
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Ben Finney
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