Calculate linear regression slope with moving window

Question

I have a dataframe and i need to automate the slope calculation by lm each 5 rows and jump 1 point and calculate slope with next 5 points and again jump 1 point and calculate slope with 5 points. And if the end of datafra when you not have 5 points put NA or no calculate slope

mtcars[c(1:5),c(1,3)] %>% mutate(slope = lm(c(mpg) ~ c(disp))$coefficients[[2]])

I need to calculate slope to next 5 points with gap = 1

mtcars[c(2:6),c(1,3)] %>% mutate(slope = lm(c(mpg) ~ c(disp))$coefficients[[2]])

Answer 1

Using map to iterate over each row number:

# toy dataset
data <- tibble(
        x = 1:50,
        y = rnorm(50))

data %>% 
        # for each row, get the coefficient of the independent variable (i.e the coefficient of x)
        mutate(model = c(map(1:(nrow(data) - 4), ~lm(y ~ x, data = data[.x:(.x + 4), ])$coefficients[2]), NA, NA, NA, NA) %>% unlist())

# A tibble: 50 × 3
       x       y   model
   <int>   <dbl>   <dbl>
 1     1 -2.52    0.775 
 2     2 -0.455   0.370 
 3     3 -0.914   0.333 
 4     4 -1.14    0.221 
 5     5  1.70   -0.214 
 6     6  0.0893  0.0863
 7     7  0.138  -0.305 
 8     8  0.748  -0.329 
 9     9  0.298  -0.239 
10    10  0.441   0.274 
# ℹ 40 more rows