Mathematica, Maple, Matlab, IDL syntax differences

Specific syntax differences between the four packages:
 
expression
 		 Mathematica Maple Matlab IDL
assign value c = 2 Pi r

delayed evaluation:
c := 2 Pi r

 c := 2 * Pi * r; c = 2 * pi * 10
(doesn't handle symbolic values)		 c = 2 * !pi * 10
(doesn't handle symbolic values)
equality If[i==j, ...] if (i=j) then ... if i==j ... if (i eq j) then ...
parameters in square brackets, e.g.,
Sqrt[ArcTan[2.3,0.19]]		 in parentheses, e.g.,
sqrt(arctan(2.3,0.19));		 in parentheses, e.g.,
sqrt(atan2(2.3,0.19));		 procedures: just comma-separated
sURFace, z, X, y

functions: in parentheses
t=aTAN(2.3,0.19)
capitalization built-in functions are all Capitalized. (user-defined functions can be named lowercase) function names usually lowercase function names lowercase case-insensitive
compound statements a=1 ; b=2 ; c=3

all statements executed, but output is suppressed for those followed by semicolon (;)

 a=1: b=2; c=3:

all statements executed, but output is suppressed for those followed by colon (:) rather than semicolon (;)

 same as Mathematica. Semicolons end/separate statements and suppress output, e.g.,

a=1 ; b=2 ; c=3

a=1 & b=2 & c=3

separate commands with ``&''
multiline statements continues to next line if the end of one line leaves any brackets or parentheses unmatched, or arithmetic operators dangling ignores newlines; looks for statements to end terminate with either `:' or `;' xxx append ``$'' to incomplete lines
multiplication either juxtaposition (separate variables by space), or `*'

c = 2 Pi r
c = 2 * Pi * r

 requires `*'

c := 2 * Pi * r;

 requires `*' requires `*'
defining matrix A=
1 2 3
4 5 6

Which element is ``6''?

 A={{1,2,3},{4,5,6}}

A[[2,3]]

 A:=Matrix([[1,2,3],[4,5,6]]);
A[2,3];		 A = [1 2 3 ; 4 5 6]
A(2,3)		 A=[[1,2,3],[4,5,6]]

A[2,1]
(column-major, and indices numbered from zero)
matrix multiplication
vTAw		 v.A.w Transpose(v).A.w v*A*transpose(w) transpose(v##A)#w
elementwise multiplication of matrices, e.g.,

A = 1 2 3 4
    5 6 7 8

B = 9 8 7 6
    5 4 3 2

 A * B

 9 16 21 24
25 24 21 16

 ? A .* B

 9 16 21 24
25 24 21 16

 A * B

 9 16 21 24
25 24 21 16
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