Row col extraction given random generated numbers

Question

For some reason, it is not clear why my code for row col extraction is not working. This sample code should work.

set.seed(42)
FX <- data.frame(Location=c(5, 7:10), mi=c(1, 34.6, 6, 44, 5.55))
RX <- data.frame(Course=runif(n=1, min=4, max=5), Cor=runif(n=1, min=2, max=3))
FX
#   Location    mi
# 1        5  1.00
# 2        7 34.60
# 3        8  6.00
# 4        9 44.00
# 5       10  5.55
RX
#     Course      Cor
# 1 4.914806 2.937075

Current code that is not working:

which(FX==RX[1,1], arr.ind=TRUE)

Desired output:

Row and all cols

Is this [R FAQ 7.31](https://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f)? Also [Why are these numbers not equal?](https://stackoverflow.com/questions/9508518/why-are-these-numbers-not-equal). — Rui Barradas, Jul 29 '21 at 21:53
There are no values in `FX` which is equal to `RX[1,1]`. What is your expected output? — Ronak Shah, Jul 30 '21 at 02:40

score 0 · Accepted Answer · answered Jul 29 '21 at 21:10

0

'RX' is just having a single row, We may need to replicate it to make the dimensions same

FX == RX[col(FX)]

Also, these are float values, so there is some precision involved i.e. it may not be exactly equal unless we do some rounding

answered Jul 29 '21 at 21:10

akrun

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Once the code is fixed and `RX` contains a value in the data, the original code works, e.g. `RX[1, 1] – dcarlson Jul 29 '21 at 21:28
@akrun, why must the data frames be equal? – Toy L Aug 01 '21 at 05:20
@ dcarlson, What is `RX[1, 1] – Toy L Aug 01 '21 at 05:22
1

@ToyL It is because of the property of `==` i.e. it is an elementwise operator. So, it needs the length to be same on lhs and rhs – akrun Aug 01 '21 at 18:38
Can't ` test_1 – Toy L Aug 03 '21 at 04:07
My concern with the `round()` operator is that with digits longer than 2, I may get multiple outputs. – Toy L Aug 03 '21 at 04:10

Row col extraction given random generated numbers

1 Answers1