I m using a data set with 41 features numerics and nominals the 42 one is the class (normal or not) first I changed all the nominals features to numeric since the autoencoder requires that the imput vector should be numeric. so the number of features incresed from 42 to 122. I removed the class colomn because AE use unlabelled data and I used it to reduce dimensionality from 121 to 10 ( 121> 50->10->50-121) now I want to build a MLP to classify the data I divided the data set into 3 parts: train, validate and test set, I want to put the 10 features selected by the AE instead of the 121 but I dont know how (code?). and how add the class colomn again to the data set to do a supervised classification with MLP?