I need to round a float to be displayed in a UI. e.g, to one significant figure:
1234 -> 1000 0.12 -> 0.1 0.012 -> 0.01 0.062 -> 0.06 6253 -> 6000 1999 -> 2000
Is there a nice way to do this using the Python library, or do I have to write it myself?
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Answer
You can use negative numbers to round integers:
>>> round(1234, -3) 1000.0
Thus if you need only most significant digit:
>>> from math import log10, floor >>> def round_to_1(x): ... return round(x, -int(floor(log10(abs(x))))) ... >>> round_to_1(0.0232) 0.02 >>> round_to_1(1234243) 1000000.0 >>> round_to_1(13) 10.0 >>> round_to_1(4) 4.0 >>> round_to_1(19) 20.0
You’ll probably have to take care of turning float to integer if it’s bigger than 1.