• The shuffle command has been moved to the Random package as Random.shuffle().
• linspace has been replaced with range(start, stop=…, length=…).
• To determine the length of a matrix, use size(…,2) instead of length().
• For accessing the first and last part of datasets, head() as been replaced with first(), and tail() with last().
• For arithmetic calculations involving constants and arrays, the better syntax const .- array needs to be used instead of const – array. In connection with this, a space might be required before the operator; i.e. to avoid confusion with number types use 1 .- array, and not 1.-array.
• Conversion of a dataframe df to a matrix can be done via convert(Matrix, df) instead of convert(Array, df).

Exercise 8

• The creation of an initially undefined vector etc. now requires the undef keyword as in activation_functions = Vector{Function}(undef, size(hidden_units,1)).
• An assignment of a function to multiple entries of a vector requires the dot-operator: activation_functions[1:end-1] .= z->nn.dropout(nn.relu(z), keep_probability)

• For this exercise to work, the MNIST.jl package needs an update. A quick fix can be found in the repository together with the exercise notebooks.
• Instead of flipdim(A, d), use reverse(A, dims=d).
• indmax has been replaced by argmax.
• Parsing expressions has been moved to the Meta package and can be done by Meta.parse(…).

• The behaviour of taking the transpose of a vector has been changed – it now creates an abstract linear algebra object. We use collect() on the transpose for functions that cannot handle the new type.
• To test if a string contains a certain word, contains() has been replaced by occursin().