using paste() in a for loop with glm

Question

In the code below, df.pts is a dataframe. I'd like to run about dozen glm models using different y variable (only two shown in the code). I'm using a for loop with the paste() function, but I can't seem to get the paste() function to work properly. What am I missing with paste()?

SPCA2 = df.pts[,3]
CLQU2 = df.pts[,4]

df.list = list(SPCA2, CLQU2)

for (i in df.list) {
    qp.mod = glm(paste(i,"~NDVI+ELEV"), family="quasipoisson", data=my.data)
    print(summary(gp.mod))
 }

Answer 1

Many thanks! The main problem was that df.list was a list of vectors, and should have been a list of names.

I other words, to correct the problem...

df.list = ("SPCA2", "CLQU2")

instead of

df.list = list(SPCA2, CLQU2)

However, it was also correctly pointed out that the dataframe, my.data, was not the correct dataframe. Finally, while it worked without it, the function as.formula() also worked. Again, many thanks!

Answer 2

您需要在paste之前添加as.formula ，以让R知道您要将其视为公式而不是字符。

qp.mod = glm(as.formula(paste(i,"~NDVI+ELEV")), family="quasipoisson", data=my.data)