CODEWITHSUNDEEP
rif-statementrange
riceresearchuser
riceresearchuser

Reputation: 1

code for creating "if... then" statement for a range of values of two variables

I am trying to create an "if... then" statement in R in which two variables, G1 and G2, lie within a range of values in a given dataset. For example, the "if...then" scenario I would like to test is:

if (200 > G1 > -100) and (200 > G2 > -100), then G = mean(G1,G2)

My code for the scenario looks like this:

if(200 > G1 > -100 & 200 > G2 > -100) {G = mean(G1,G2)}

The error that I getting reads:

Error: unexpected '>' in "        if(200 > G1 >"

Any help would be much appreciated! Thanks

UPDATE:

G1 and G2 are two lists of values in a data frame

Here is an example:

G1 = 101, G2 = 2

Expected output: G = mean(101,2) = 51.5

Upvotes: 0

Views: 87

Answers (2)

GuedesBF
GuedesBF

Reputation: 9868

If you have your G1 and G2 in a dataframe, you can use dplyr::mutate() rowMeans() and replace() values in rows not meeting the conditions with NA.

df%>%mutate(conditioned_mean=rowMeans(.)%>%
                    replace(., !if_all(G1:G2, ~.x>-100 & .x<200), NA))

   G1   G2 conditioned_mean
1 125 -123               NA
2 135  122            128.5
3 142  180            161.0
4 215  140               NA

Data

G1 <- c(125, 135, 142, 215)
G2 <- c(-123, 122, 180, 140)
df<-data.frame(G1, G2)

Upvotes: 1

akrun
akrun

Reputation: 887511

The R syntax is incorrect. It is different from the mathematical syntax

if(G1 > -100 &  G1< 200 & G2 > -100 & G2 < 200) G <- mean(c(G1, G2))

-output

G
[1] 137.5

Having said that the if/else works only when 'G1', 'G2' are of length 1 and not greater than 1 as if/else is not vectorized i.e. if the length is more than 1, use the vectorized ifelse or create a logical index, subset the values of 'G1', 'G2' based on that index and get the mean

G1 <- c(125, 135, 142, 215)
G2 <- c(-123, 122, 180, 140)
i1 <- G1 > -100 &  G1< 200 & G2 > -100 & G2 < 200
 mean(c(G1[i1], G2[i1]))
[1] 144.75

Or if we are interested in the mean of corresponding elements that meet the condition, then cbind the objects to a matrix, subset the rows with 'i1' and get the rowMeans

rowMeans(cbind(G1, G2)[i1,])
[1] 128.5 161.0

data

G1 <- 150
G2 <- 125

Upvotes: 1

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