2+2

x=2

x=2;

Union[{1,3,2,4,3},{2,7,8}]

Union[{1,3,2,4,3}]

Union[]

Sort[{1,3,2,4,3}]

Intersection[{1,3,2,4,3}]

head[arg1,arg2,...,argk]

Graphics[Circle[]]

Head[Graphics[Circle[]]]

Head[f[3,4]]

Plus[2,3]

2+3

Head[2+3]

Head[Plus[2,3]]

Head[a+b]

FullForm[a+b]

FullForm[a^p+b j]

FullForm[{0,0}]

FullForm[Graphics[Circle[]]]

?Circle

?Apply

Apply[f,g[a,b]]

Apply[f,a+b]

Apply[f,a b]

Apply[f,a^b]

Apply[f,{a,b}]

Apply[Times,a+b]

?Total

Total[{a,b,c,d,e}]

FullForm[{a,b,c,d,e}]

Apply[Plus,{a,b,c,d,e}]

Power[a,b]

Apply[Power,{a,b,c,d,e}]

Apply[Subtract,{a,b,c,d,e}]

Apply[Minus,{a,b,c,d,e}]

?Map

Clear[x]

Map[f,x+y z]

f/@(x+y z)

f/@{x,y z}

Union[g[a,b,a]]

Compute the radical (product of the prime divisors) of an integer.

?FactorInteger

FactorInteger[12346 36]

First/@FactorInteger[12346 36]

Times@@First/@FactorInteger[12346 36]

Apply[Times,Map[First,FactorInteger[12346 36]]]

Radical[n_]:=Times@@First/@FactorInteger[n]

Radical[100]

?Select

Select[{1,2,3,4,5},PrimeQ]

Range[1,100]

Select[Range[1,100],PrimeQ]

?Length

Select[Range[1,100],Function[n,Length[FactorInteger[n]]==2]]

Write TielessGames without If or For.

TielessGames[list_,0]:={{}}
TielessGames[list_,n_]:=
Flatten[
Function[game,
Function[score,
Append[game,score]
]/@Complement[list,{-Total[game]}]
]/@
TielessGames[list,n-1],
1
]

?Accumulate

Accumulate/@TielessGames[{1,-1},5]

Flatten[{{{1,2},{3,4}},{{1,2},{3,4}}},1]

?Flatten

?GraphData

Length[GraphData[]]

GraphData["ChvatalGraph"]

GraphData["ChvatalGraph","Classes"]

GraphData["PetersenGraph","AllImages"]

GraphData["Biconnected"]

?KnotData

?PolyhedronData

Length[PolyhedronData[]]

PolyhedronData[All,"Image"]

?CountryData

CountryData["USA","Properties"]

?Manipulate

Manipulate[x^2,{x,0,10}]

Manipulate[ContourPlot3D[p[[1]] x^3+p[[2]] y^2-z^2,{x,-2,2},{y,-2,2},{z,-2,2}],{{p,{.3,.4}},{0,0},{1,1}}]

Manipulate[Graphics[{Circle[p,Norm[p]],Polygon[{p,q,r}]},PlotRange->10],{{p,{2,2}},Locator},{{q,{7,-4}},Locator,Appearance->None},{{r,{-6,5}},Locator}]