Hello,

You're right, I carelessly coded this.

which.max returns the index to the first maximum of a vector, while the comparison of a vector with its max() returns an index to all vector elements.

Às 23:27 de 03/12/21, Bert Gunter escreveu:
Perhaps you meant to point this out, but the cfs[which.max(cfs)] and
cfs == ... are not the same:

x <- rep(1:2,3)
x
[1] 1 2 1 2 1 2
x[which.max(x)]
[1] 2
x[x==max(x)]
[1] 2 2 2

So maybe your point is: which does the OP want (in case there are
repeated maxes)? I suspect the == forms, but ...?

Bert Gunter

On Fri, Dec 3, 2021 at 2:56 PM Rui Barradas <ruipbarra...@sapo.pt> wrote:

Hello,

Inline.

Às 22:08 de 03/12/21, Rich Shepard escreveu:
On Fri, 3 Dec 2021, Rich Shepard wrote:

I find solutions when the data_frame is grouped, but none when it's not.

Thanks, Bert. ?which.max confirmed that's all I need to find the maximum
value.

Now I need to read more than ?filter to learn why I'm not getting the
relevant row with:
which.max(pdx_disc$cfs)
[1] 8054

This is the *index* for which cfs is the first maximum, not the maximum
value itself.


filter(pdx_disc, cfs == 8054)

Therefore, you probably want any of

Should be "one of", not "any of"

Rui Barradas



filter(pdx_disc, cfs == cfs[8054])

filter(pdx_disc, cfs == cfs[which.max(cfs)])

filter(pdx_disc, cfs == max(cfs))    # I find this one better, simpler


Hope this helps,

Rui Barradas


# A tibble: 0 × 9
# … with 9 variables: site_nbr <chr>, year <int>, mon <int>, day <int>,
#   hr <dbl>, min <dbl>, tz <chr>, cfs <dbl>, sampdt <dttm>

Regards,

Rich

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