How should I get the coefficients of Lasso Model?

问题

Here is my code:

library(MASS)
library(caret)
df <- Boston
set.seed(3721)
cv.10.folds <- createFolds(df$medv, k = 10)
lasso_grid <- expand.grid(fraction=c(1,0.1,0.01,0.001))
lasso <- train(medv ~ ., 
               data = df, 
               preProcess = c("center", "scale"),
               method ='lasso',
               tuneGrid = lasso_grid,
               trControl= trainControl(method = "cv", 
                                       number = 10, 
                                       index = cv.10.folds))  

lasso

Unlike linear model, I cannot find the coefficients of Lasso regression model from summary(lasso). How should I do that? Or maybe I can use glmnet?

来源：https://stackoverflow.com/questions/41797792/how-should-i-get-the-coefficients-of-lasso-model