Approximately equal numeric fields

[dan-blanchard]

It'd be really nice if there was some way to say "Consider numeric values equivalent if they're equal to a certain number of decimal places."

Here's a simple function for doing so from Stack Overflow:

def nearly_equal(a, b, sig_fig=5):
    return (a == b or 
            int(a * 10**sig_fig) == int(b * 10**sig_fig))

[larsyencken]

That's an excellent suggestion.

Out of curiosity, what's your use case? What types of things are you comparing?

[dan-blanchard]

I'm comparing the output of a system that generates many columns of floats. Because of floating point precision nonsense, when I run it on different machines the outputs differ after the 9th decimal and I don't care about those differences. I'm trying to find more substantial differences that would indicate an error.

[ivansabik]

This issue is really old is really old but I find myself also using that a lot. My specific case is I use a lot of times Excel for editing the new file I want to compare against to (for instance I remove columns so that it matches the other one). Our friend Excel likes adding .00 (or removing those not sure exactly now) and since string/text comparison is being done currently it accounts for it as modified. Still working on adding other feature I use a lot (xlsx export) but once I'm done with that might take a look at this one.