Flatten[list] flattens out nested lists.
Flatten[list, n] flattens to level n.
Flatten[list, n, h] flattens subexpressions with head h.
Example: Flatten[a,b,c,d] .
Flatten "unravels" lists, effectively just deleting inner braces.
Flatten[list, n] effectively flattens the top level in list n times.
Flatten[f[e, ... ]] flattens out subexpressions with head f.
Flatten flattens out levels in SparseArray objects just as in the corresponding ordinary arrays.
See Section 1.8.12 and Section 2.2.10.
See also: Partition, FlattenAt.
New in Version 1.