T-T - 6 months ago 37

R Question

What I am trying to do is pretty simple. However, I am new to R and have not learned much about loops and functions and am not sure what is the most efficient way to get the results. Basically, I want to count the number of rows that meet my conditions and do a division. Here is an example:

`df1 <- data.frame(`

Main = c(0.0089, -0.050667, -0.030379, 0.066484, 0.006439, -0.026076),

B = c(NA, 0.0345, -0.0683, -0.052774, 0.014661, -0.040537),

C = c(0.0181, 0, -0.056197, 0.040794, 0.03516, -0.022662),

D = c(-0.0127, -0.025995, -0.04293, 0.057816, 0.033458, -0.058382)

)

df1

# Main B C D

# 1 0.008900 NA 0.018100 -0.012700

# 2 -0.050667 0.034500 0.000000 -0.025995

# 3 -0.030379 -0.068300 -0.056197 -0.042930

# 4 0.066484 -0.052774 0.040794 0.057816

# 5 0.006439 0.014661 0.035160 0.033458

# 6 -0.026076 -0.040537 -0.022662 -0.058382

My criteria for the numerator is to count the number of

`B/C/D`

`>0`

`Main`

`>0`

`B/C/D`

`!= 0`

`Main`

`!= 0`

`length(which(df1$Main >0 & df1$B>0)) / length(which(df1$Main !=0 & df1$B !=0))`

`# B C D`

# 1 0.2 0.6 0.3

Answer

Use apply:

```
apply(df1[,-1], 2, function(x) length(which(df1$Main >0 & x>0)) / length(which(df1$Main !=0 & x !=0)))
```

Source (Stackoverflow)