Linear model function lm() error: NA/NaN/Inf in foreign function call (arg 1)

Question

Say I have data.frame a

I use

m.fit <- lm(col2 ~ col3 * col4, na.action = na.exclude)

col2 has some <

Answer 1

I got this error when I inverted the arguments when calling reformulate and use the formula in my lm call without checking, so I had the wrong predictor and response variable.