• → Map

Apply (@@)

WMA link

Apply[f, expr]

f @@ expr

replaces the head of expr with f.

Apply[f, expr, levelspec]

applies f on the parts specified by levelspec.

• • f @@ {1, 2, 3}

• • Plus @@ {1, 2, 3}

The head of expr need not be List:

• • f @@ (a + b + c)

Use the operator form of Apply:

• • Apply[f][a + b + c]

Apply on level 1:

• • Apply[f, {a + b, g[c, d, e * f], 3}, {1}]

The default level is 0:

• • Apply[f, {a, b, c}, {0}]

Range of levels, including negative level (counting from bottom):

• • Apply[f, {{{{{a}}}}}, {2, -3}]

Convert all operations to lists:

• • Apply[List, a + b * c ^ e * f[g], {0, Infinity}]