Flatten

Flatten[list]
flattens out nested lists.

Flatten[list,n]
flattens to level n.

Flatten[list,n,h]
flattens subexpressions with head h.

Flatten[list,{{s11,s12,},{s21,s22,},}]
flattens list by combining all levels to make each level i in the result.

DetailsDetails

  • 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.
  • If the are matrices, Flatten[{{m11,m12},{m21,m22}},{{1,3},{2,4}}] effectively constructs a single matrix from the "blocks" .
  • Flatten[list,{{i1},{i2},}] effectively transposes levels in list, putting level in list at level k in the result. Note that the function Transpose in effect uses an inverse of this specification.
  • Flatten flattens out levels in SparseArray objects just as in the corresponding ordinary arrays. »
Introduced in 1988
(1.0)
| Updated in 2007
(6.0)