Ah, I forgot, it wasn't in julia-users, it was in julia-dev!
https://groups.google.com/forum/#!topic/julia-dev/KloaO7zTYwo
On Thursday, June 18, 2015 at 10:30:05 AM UTC-4, Tom Breloff wrote:
>
> Scott: I remember there being another discussion but I can't seem to find
> it. How did you try to get in touch? Do you want to start a github issue
> and I'll comment there?
>
> On Thursday, June 18, 2015 at 10:20:08 AM UTC-4, Scott Jones wrote:
>>
>> This was already discussed recently, here on julia-users, I'm trying to
>> get in touch with Dahua Lin (author of Formatting.jl)
>> to see about adding a simpler `sfmt` that would help with this).
>>
>> On Thursday, June 18, 2015 at 10:13:46 AM UTC-4, Tom Breloff wrote:
>>>
>>> I wonder if what we really need is just some extra additions to
>>> Formatting.jl (since I think this is the best place to keep standard
>>> formatting calls). We could add fmt2, fmt3, etc which would be meant for
>>> formatting floats to that precision. I suspect that's the most common use
>>> of formatting. Additionally, just a shorter name than "generate_formatter"
>>> might help adoption for non-standard formatting. If this makes sense to
>>> people, I'll start an issue on github, and perhaps a PR as well.
>>>
>>>
>>> julia> using Formatting
>>>
>>> julia> fmt2 = generate_formatter("%1.2f")
>>> sprintf_JTEuMmY! (generic function with 1 method)
>>>
>>> julia> fmt3 = generate_formatter("%1.3f")
>>> sprintf_JTEuM2Y! (generic function with 1 method)
>>>
>>> julia> @time fmt2(31231.345435245)
>>> 55.763 milliseconds (33974 allocations: 1444 KB)
>>> "31231.35"
>>>
>>> julia> @time fmt2(31231.345435245)
>>> 13.573 microseconds (15 allocations: 608 bytes)
>>> "31231.35"
>>>
>>> julia> @time fmt3(31231.345435245)
>>> 11.193 milliseconds (5882 allocations: 254 KB)
>>> "31231.345"
>>>
>>> julia> @time fmt3(31231.345435245)
>>> 16.231 microseconds (15 allocations: 608 bytes)
>>> "31231.345"
>>>
>>>
>>>
>>>
>>> On Thursday, June 18, 2015 at 3:55:01 AM UTC-4, cormu...@mac.com wrote:
>>>>
>>>> You could use a type:
>>>>
>>>> julia> type Out
>>>> n::Float64
>>>> end
>>>>
>>>> julia> function Base.show(io::IO, n::Out)
>>>> print(io, "$(round(n.n, 2))")
>>>> end
>>>> show (generic function with 83 methods)
>>>>
>>>> then you can just use Out(x) whenever you want x rounded to 2 d.p.
>>>>
>>>> julia> for i in 0.7454539:1.5:5
>>>> println("i is $i and displayed as $(Out(i))")
>>>> end
>>>> i is 0.7454539 and displayed as 0.75
>>>> i is 2.2454539000000002 and displayed as 2.25
>>>> i is 3.7454539000000002 and displayed as 3.75
>>>>
>>>>
