[R] howto find x value where x=max(x)

[Jonas Stein]

Hi,

fp is a data frame like this

,----[ fp ]
|    Frequenz      AmpNorm
| 1      3322 0.0379490639
| 2      3061 0.0476033058
| 3      2833 0.0592954124
| 4      2242 0.1275510204
`----

i want to find the "Frequenz" where "AmpNorm" is max.

I use this line as workaround:
PeakFreqHz = subset(fp, AmpNorm == max(AmpNorm))$Frequenz[1]

Is there something nicer?
And is there an easy way to do the same on "predict()"

Thank you and kind regards,

-- 
Jonas Stein <news at jonasstein.de>