Want to obtain the detail of training errors

In a Keras model I want to obtain the training errors as a list or array, ie, e[i]=y[i]-yest[i] for each i in the training dataset, for the last epoch. This is usual in an econometric model but I do not see to obtaining in Machine Learning, where only the Mae or Mse is reported by epoch.

Deliverables
Code to include in a Keras model