You can use copy and deepcopy :
help?> copy search: copy copy! copysign deepcopy unsafe_copy! cospi complex Complex complex64 complex32 complex128 complement copy(x) Create a shallow copy of x: the outer structure is copied, but not all internal values. For example, copying an array produces a new array with identically-same elements as the original. help?> deepcopy search: deepcopy deepcopy(x) Create a deep copy of x: everything is copied recursively, resulting in a fully independent object. For example, deep-copying an array produces a new array whose elements are deep copies of the original elements. Calling deepcopy on an object should generally have the same effect as serializing and then deserializing it. As a special case, functions can only be actually deep-copied if they are anonymous, otherwise they are just copied. The difference is only relevant in the case of closures, ie functions which may contain hidden internal references. While it isn't normally necessary, user-defined types can override the default deepcopy behavior by defining a specialized version of the function deepcopy_internal(x::T, dict::ObjectIdDict) (which shouldn't otherwise be used), where T is the type to be specialized for, and dict keeps track of objects copied so far within the recursion. Within the definition, deepcopy_internal should be used in place of deepcopy, and the dict variable should be updated as appropriate before returning.
Like this:
julia> a = Any[1, 2, 3, [4, 5, 6]] 4-element Array{Any,1}: 1 2 3 [4,5,6] julia> b = copy(a); c = deepcopy(a); julia> a[4][1] = 42; julia> b
Please note that the help system indicates the presence of other functions related to copying.