Computer Algebra I: Mathematica, SymPy, Sage, Maxima

a side-by-side reference sheet

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	mathematica	sympy	sage	maxima
version used	10.0	Python 2.7; SymPy 0.7	6.10	5.37
show version	select About Mathematica in Mathematica menu	sympy.__version__	$ sage --version also displayed on worksheet	$ maxima --version
implicit prologue		from sympy import * # enable LaTeX rendering in Jupyter notebook: init_printing() # unknown variables must be declared: x, y = symbols('x y')	# unknowns other than x must be declared: y = var('y')
grammar and invocation
	mathematica	sympy	sage	maxima
interpreter	$ cat > hello.m Print["Hello, World!"] $ MathKernel -script hello.m	if foo.py imports sympy: $ python foo.py	$ cat > hello.sage print("Hello, World!") $ sage hello.sage	$ cat >> hello.max print("Hello, world!"); $ maxima -b hello.maxima
repl	$ MathKernel	$ python >>> from sympy import *	$ sage	$ maxima
block delimiters	( stmt; …)	: and offside rule	: and offside rule	block([x: 3, y: 4], x + y); /* Multiple stmts are separated by commas; a list of assignments can be used to set variables local to the block. */
statement separator	; or sometimes newline A semicolon suppresses echoing value of previous expression.	newline or ; newlines not separators inside (), [], {}, triple quote literals, or after backslash: \	newline or ; newlines not separators inside (), [], {}, triple quote literals, or after backslash: \	; or $ The dollar sign $ suppresses output.
end-of-line comment	none	1 + 1 # addition	1 + 1 # addition	none
multiple line comment	1 + (* addition *) 1	none	none	1 + /* addition */ 1;
variables and expressions
	mathematica	sympy	sage	maxima
assignment	a = 3 Set[a, 3] (* rhs evaluated each time a is accessed: *) a := x + 3 SetDelayed[a, x + 3]	a = 3	a = 3	a: 3;
parallel assignment	{a, b} = {3, 4} Set[{a, b}, {3, 4}]	a, b = 3, 4	a, b = 3, 4	[a, b]: [3, 4]
compound assignment	+= -= = /= corresponding functions:* AddTo SubtractFrom TimeBy DivideBy	+= -= = /= //= %= ^= *=	+= -= = /= //= %= *=	none
increment and decrement	++x --x PreIncrement[x] PreDecrement[x] x++ x-- Increment[x] Decrement[x]	none	none	none
non-referential identifier	any unassigned identifier is non-referential	x, y, z, w = symbols('x y z w')	y, z, w = var('y z w') # x is non-referential unless assigned a value	any unassigned identifier is non-referential
identifier as value	x = 3 y = HoldForm[x]			x: 3; y: 'x;
global variable	variables are global by default	g1, g2 = 7, 8 def swap_globals(): global g1, g2 g1, g2 = g2, g1	g1, g2 = 7, 8 def swap_globals(): global g1, g2 g1, g2 = g2, g1	variables are global by default
local variable	Module[{x = 3, y = 4}, Print[x + y]] (* makes x and y read-only: ) With[{x = 3, y = 4}, Print[x + y]] ( Block[ ] declares dynamic scope *)	assignments inside functions are to local variables by default	assignments inside functions are to local variables by default	block([x: 3, y: 4], print(x + y));
null	Null	None	None	no null value
null test	x == Null	x is None	x is None	no null value
undefined variable access	treated as an unknown number	raises NameError	raises NameError	treated as an unknown number
remove variable binding	Clear[x] Remove[x]	del x	del x	kill(x);
conditional expression	If[x > 0, x, -x]	x if x > 0 else -x	x if x > 0 else -x	if x < 0 then -x else x;
arithmetic and logic
	mathematica	sympy	sage	maxima
true and false	True False	True False	True False	true false
falsehoods	False	False 0 0.0	False None 0 0.0 '' [] {}
logical operators	! True \|\| (True && False) Or[Not[True], And[True, False]]	Or(Not(True), And(True, False)) # when arguments are symbols: ~ x \| (y & z)		and or not
relational expression	1 < 2			is(1 < 2);
relational operators	== != > < >= <= corresponding functions: Equal Unequal Greater Less GreaterEqual LessEqual	Eq Ne Gt Lt Ge Le # when arguments are symbols: == != > < >= <=	== != > < >= <=	= # > < >= <=
arithmetic operators	+ - * / Quotient Mod adjacent terms are multiplied, so is not necessary.* Quotient and Mod are functions, not binary infix operators. These functions are also available: Plus Subtract Times Divide	+ - * / ?? % if an expression contains a symbol, then the above operators are rewritten using the following classes: Add Mul Pow Mod	+ - * / // %	+ - * / quotitent() mod() quotient and mod are functions, not binary infix operators.
integer division	Quotient[a, b]		7 // 3	quotient(7, 3);
integer division by zero	dividend is zero: Indeterminate otherwise: ComplexInfinity		raises ZeroDivisionError	error
float division	exact division: a / b			a / b
float division by zero	dividend is zero: Indeterminate otherwise: ComplexInfinity			error
power	2 ^ 32 Power[2, 32]	2 ** 32 Pow(2, 32)	2 ^ 32 2 ** 32	2 ^ 32; 2 ** 32;
sqrt	returns symbolic expression: Sqrt[2]	sqrt(2)	sqrt(2)	sqrt(2);
sqrt -1	I	I	I	%i
transcendental functions	Exp Log Sin Cos Tan ArcSin ArcCos ArcTan ArcTan ArcTan accepts 1 or 2 arguments	exp log sin cos tan asin acos atan atan2	exp log sin cos tan asin acos atan atan2	exp log sin cos tan asin acos atan atan2
transcendental constants π and Euler's number	Pi E EulerGamma	pi E	pi e euler_gamma	%pi %e %gamma
float truncation round towards zero, round to nearest integer, round down, round up	IntegerPart Round Floor Ceiling	floor ceiling	int round floor ceil	truncate round floor ceiling
absolute value and signum	Abs Sign	Abs sign	abs sign	abs sign sign returns pos, neg, or zero
integer overflow	none, has arbitrary length integer type	none, has arbitrary length integer type	none, has arbitrary length integer type	none, has arbitrary length integer type
float overflow	none			none
rational construction	2 / 7	Mul(2, Pow(7, -1)) Rational(2, 7)	2 / 7	2 / 7
rational decomposition	Numerator[2 / 7] Denominator[2 / 7]	numer, denom = fraction(Rational(2, 7))	numerator(2 / 7) denominator(2 / 7)	num(2 / 7); denom(2 / 7);
decimal approximation	N[2 / 7] 2 / 7 + 0. 2 / 7 // N N[2 / 7, 100]	N(Rational(2, 7)) N(Rational(2, 7), 100)	n(2 / 7) n(2 / 7, 100) # synonyms for n: N(2 / 7) numerical_approx(2 / 7)	2 / 7, numer;
complex construction	1 + 3I	1 + 3 * I	1 + 3 * I	1 + 3 * %i;
complex decomposition real and imaginary part, argument and modulus, conjugate	Re Im Arg Abs Conjugate	re im Abs arg conjugate	(3 + I).real() (3 + I).imag() abs(3 + I) arg(3 + I) (3 + I).conjugate()	realpart imagpart cabs carg conjugate
random number uniform integer, uniform float	RandomInteger[{0, 99}] RandomReal[]			random(100); random(1.0);
random seed set, get	SeedRandom[17] ??			set_random_state(make_random_state(17)); ??
bit operators	BitAnd[5, 1] BitOr[5, 1] BitXor[5, 1] BitNot[5] BitShiftLeft[5, 1] BitShiftRight[5, 1]			none
binary, octal, and hex literals	2^^101010 8^^52 16^^2a			ibase: 2; 101010; ibase: 8; 52; /* If first hex digit is a letter, prefix a zero: */ ibase: 16; 2a;
radix	BaseForm[42, 7] BaseForm[7^^60, 10]			obase: 7; 42;
to array of digits	(* base 10: ) IntegerDigits[1234] ( base 2: *) IntegerDigits[1234, 2]
strings
	mathematica	sympy	sage	maxima
string literal	"don't say \"no\""	use Python strings	use Python strings	"don't say \"no\""
newline in literal	yes			Newlines are inserted into strings by continuing the string on the next line. However, if the last character on a line inside a string is a backslash, the backslash and the following newline are omitted.
literal escapes	\\ \" \b \f \n \r \t \ooo			\" \\
concatenate	"one " <> "two " <> "three"			concat("one ", "two ", "three");
translate case	ToUpperCase["foo"] ToLowerCase["FOO"]			supcase("foo"); sdowncase("FOO");
trim	StringTrim[" foo "]			strim(" ", " foo ");
number to string	"value: " <> ToString[8]			concat("value: ", 8);
string to number	7 + ToExpression["12"] 73.9 + ToExpression[".037"]			7 + parse_string("12"); 73.9 + parse_string(".037"); /* parse_string raises error if the string does not contain valid Maxima code. Use numberp predicate to verify that the return value is numeric. */
string join	StringJoin[Riffle[{"foo", "bar", "baz"}, ","]]			simplode(["foo", "bar", "baz"], ",");
split	StringSplit["foo,bar,baz", ","]			split("foo,bar,baz", ",");
substitute first occurrence, all occurences	s = "do re mi mi" re = RegularExpression["mi"] StringReplace[s, re -> "ma", 1] StringReplace[s, re -> "ma"]			ssubst("mi", "ma", "do re mi mi mi"); ssubstfirst("mi", "ma", "do re mi mi mi");
length	StringLength["hello"]			slength("hello");
index of substring	StringPosition["hello", "el"][[1]][[1]] (* The index of the first character is 1.) ( StringPosition returns an array of pairs, one for each occurrence of the substring. Each pair contains the index of the first and last character of the occurrence. *)			ssearch("el", "hello"); /* 1 is index of first character; returns false if substring not found */ _
extract substring	(* "el": *) StringTake["hello", {2, 3}]			substring("hello", 2, 4);
character literal	none			none
character lookup	Characters["hello"][[1]]
chr and ord	FromCharacterCode[{65}] ToCharacterCode["A"][[1]]			ascii(65); cint("A");
delete characters	rules = {"a" -> "", "e" -> "", "i" -> "", "o" -> "", "u" -> ""} StringReplace["disemvowel me", rules]
arrays
	mathematica	sympy	sage	maxima
literal	{1, 2, 3} List[1, 2, 3]	use Python lists	use Python lists	[1, 2, 3];
size	Length[{1, 2, 3}]			length([1, 2, 3]);
lookup	(* access time is O(1) ) ( indices start at one: *) {1, 2, 3}[[1]] Part[{1, 2, 3}, 1]			a: [6, 7, 8]; a[1];
update	a[[1]] = 7			a[1]: 7;
out-of-bounds behavior	left as unevaluated Part[] expression			Error for both lookup and update.
element index	(* Position returns list of all positions: *) First /@ Position[{7, 8, 9, 9}, 9]			a: [7, 8, 9, 9]; first(sublist_indices(a, lambda([x], x = 9)));
slice	{1, 2, 3}[[1 ;; 2]]
array of integers as index	(* evaluates to {7, 9, 9} *) {7, 8, 9}[[{1, 3, 3}]]
manipulate back	a = {6,7,8} AppendTo[a, 9] elem = a[[Length[a]]] a = Delete[a, Length[a]] elem
manipulate front	a = {6, 7, 8} PrependTo[a, 5] elem = a[[1]] a = Delete[a, 1] elem			a: [6, 7, 8]; push(5, a); elem: pop(a);
head	First[{1, 2, 3}]			first([1, 2, 3]);
tail	Rest[{1, 2, 3}]			rest([1, 2, 3]);
cons	(* first arg must be an array *) Prepend[{2, 3}, 1]			cons(1, [2, 3]);
concatenate	Join[{1, 2, 3}, {4, 5, 6}]			append([1, 2, 3], [4, 5, 6]);
replicate	tenZeros = Table[0, {i, 0, 9}]			ten_zeros: makelist(0, 10);
copy	a2 = a			a2: copylist(a);
iterate	Do[Print[i], {i, {1, 2, 3}}]			for i in [1, 2, 3] do print(i);
reverse	Reverse[{1, 2, 3}]			reverse([1, 2, 3]);
sort	(* original list not modified: *) a = Sort[{3, 1, 4, 2}]			sort([3, 1, 4, 2]);
dedupe	DeleteDuplicates[{1, 2, 2, 3}]			unique([1, 2, 2, 3]);
membership	MemberQ[{1, 2, 3}, 2]			member(7, {1, 2, 3}); evalb(7 in {1, 2, 3});
map	Map[Function[x, x x], {1, 2, 3}] Function[x, x x] /@ {1, 2, 3} (* if function has Listable attribute, Map is unnecessary: ) sqr[x_] := x x SetAttributes[sqr, Listable] sqr[{1, 2, 3, 4}]			map(lambda([x], x * x), [1, 2, 3]);
filter	Select[{1, 2, 3}, # > 2 &]			sublist([1, 2, 3], lambda([x], x > 2));
reduce	Fold[Plus, 0, {1, 2, 3}]
universal and existential tests	none
min and max element	Min[{6, 7, 8}] Max[{6, 7, 8}]			apply(min, [6, 7, 8]); apply(max, [6, 7, 8]);
shuffle and sample	x = {3, 7, 5, 12, 19, 8, 4} RandomSample[x] RandomSample[x, 3]
flatten one level, completely	Flatten[{1, {2, {3, 4}}}, 1] Flatten[{1, {2, {3, 4}}}]			/* completely: */ flatten([1, [2, [3, 4]]]);
zip	(* list of six elements: ) Riffle[{1, 2, 3}, {"a", "b", "c"}] ( list of lists with two elements: ) Inner[List, {1, 2, 3}, {"a", "b", "c"}, List] ( same as Dot[{1, 2, 3}, {2, 3, 4}]: *) Inner[Times, {1, 2, 3}, {2, 3, 4}, Plus]			/* list of six elements: */ join([1, 2, 3], ["a", "b", "c"]);
cartesian product	Outer[List, {1, 2, 3}, {"a", "b", "c"}]
sets
	mathematica	sympy	sage	maxima
literal	(* same as arrays: *) {1, 2, 3}	{1, 2, 3}	{1, 2, 3}	{1, 2, 3}
size	Length[{1, 2, 3}]	len({1, 2, 3})	len({1, 2, 3})	cardinality({1, 2, 3});
array to set	DeleteDuplicates[{1, 2, 2, 3}]	set([1, 2, 3])	set([1, 2, 3])	setify([1, 2, 3]);
set to array	none; sets are arrays	list({1, 2, 3})	list({1, 2, 3})	listify({1, 2, 3});
membership test	MemberQ[{1, 2, 3}, 7]	7 in {1, 2, 3}	7 in {1, 2, 3}	elementp(7, {1, 2, 3});
subset test	SubsetQ[{1, 2, 3}, {1, 2}]	{1, 2} <= {1, 2, 3} {1, 2}.issubset({1, 2, 3}) {1, 2, 3} >= {1, 2} {1, 2, 3}.issuperset({1, 2})	{1, 2} <= {1, 2, 3} {1, 2}.issubset({1, 2, 3}) {1, 2, 3} >= {1, 2} {1, 2, 3}.issuperset({1, 2})	subsetp({1, 2}, {1, 2, 3});
universal and existential tests				every(lambda([x], x > 2), [1, 2, 3]); some(lambda([x], x > 2), [1, 2, 3]);
union	Union[{1, 2}, {2, 3, 4}]	{1, 2, 3} \| {2, 3, 4} {1, 2, 3}.union({2, 3, 4})	{1, 2, 3} \| {2, 3, 4} {1, 2, 3}.union({2, 3, 4})	union({1, 2, 3}, {2, 3, 4});
intersection	Intersect[{1, 2}, {2, 3, 4}]	{1, 2, 3} & {2, 3, 4} {1, 2, 3}.intersection({2, 3, 4})	{1, 2, 3} & {2, 3, 4} {1, 2, 3}.intersection({2, 3, 4})	intersection({1, 2, 3}, {2, 3, 4});
relative complement	Complement[{1, 2, 3}, {2}]	{1, 2, 3} - {2, 3, 4} {1, 2, 3}.difference({2, 3, 4})	{1, 2, 3} - {2, 3, 4} {1, 2, 3}.difference({2, 3, 4})	setdifference({1, 2, 3}, {2, 3, 4});
powerset			set(Set({1, 2, 3}).subsets())	powerset({1, 2, 3});
cartesian product	Outer[List, {1, 2, 3}, {"a", "b", "c"}]			cartesian_product({1, 2, 3}, {"a", "b", "c"});
arithmetic sequences
	mathematica	sympy	sage	maxima
unit difference	Range[1, 100]	range(1, 101)	range(1, 101)	makelist(i, i, 1, 100);
difference of 10	Range[1, 100, 10]	range(1, 100, 10)	range(1, 100, 10)	makelist(i, i, 1, 100, 10);
difference of 1/10	Range[1, 100, 1/10]	[1 + Rational(1,10)*i for i in range(0, 991)]	[1 + (1/10)*i for i in range(0, 991)]	makelist(i, i, 1, 100, 1/10);
dictionaries
	mathematica	sympy	sage	maxima
literal	d = <\|"t" -> 1, "f" -> 0\|> (* or convert list of rules: ) d = Association[{"t" -> 1, "f" -> 0}] ( and back to list of rules: *) Normal[d]	use Python dictionaries	use Python dictionaries	d: [["t", 1], ["f", 0]];
size	Length[Keys[d]]			length(d);
lookup	d["t"]			assoc("t", d);
update	d["f"] = -1			d2: cons(["f", -1], sublist(d, lambda([p], p[1] # "f")));
missing key behavior	Returns a symbolic expression with head "Missing". If the lookup key was "x", the expression is: Missing["KeyAbsent", "x"]			assoc returns false
is key present	KeyExistsQ[d, "t"]
iterate
keys and values as arrays	Keys[d] Values[d]			map(lambda([p], p[1]), d); map(lambda([p], p[2]), d);
sort by values	Sort[d]
functions
	mathematica	sympy	sage	maxima
define function	Add[a_, b_] := a + b (* alternate syntax: *) Add = Function[{a, b}, a + b]			add(a, b) := a + b; define(add(a, b), a + b); /* block body: / add(a, b) := block(print("adding", a, "and", b), a + b); / square bracket syntax: */ I[row, col] := if row = col then 1 else 0; I[10, 10];
invoke function	Add[3, 7] Add @@ {3, 7} (* syntax for unary functions: *) 2 // Log			add(3, 7);
boolean function attributes list, set, clear	Attributes[add] SetAttributes[add, {Orderless, Flat, Listable}] ClearAtttibutes[add, Listable]
undefine function	Clear[Add]			remfunction(add);
redefine function	Add[a_, b_] := b + a			add(a, b) := b + a;
missing function behavior	The expression is left unevaluated. The head is the function name as a symbol, and the parts are the arguments.			The expression is left unevaluated.
missing argument behavior	The expression is left unevaluated. The head is the function name as a symbol, and the parts are the arguments.			Too few arguments error.
extra argument behavior	The expression is left unevaluated. The head is the function name as a symbol, and the parts are the arguments.			Too many arguments error.
default argument	Options[myLog] = {base -> 10} myLog[x_, OptionsPattern[]] := N[Log[x]/Log[OptionValue[base]]] (* call using default: ) myLog[100] ( override default: *) myLog[100, base -> E]
return value	last expression evaluated, or argument of Return[]			last expression evaluated Inside a block(), the last expression evaluated or the argument of return()
anonymous function	Function[{a, b}, a + b] (#1 + #2) &			f: lambda([x, y], x + y); f(3, 7);
variable number of arguments	(* one or more arguments: ) add[a__] := Plus[a] ( zero or more arguments: *) add[a___] := Plus[a]			add([a]) := sum(a[i], i, 1, length(a));
pass array elements as separate arguments	Apply[f, {a, b, c}] f @@ {x, y, z}	a = [x, y, z] f(*a)		add(a, b) := a + b; apply(add, [3, 7]);
execution control
	mathematica	sympy	sage	maxima
if	If[x > 0, Print["positive"], If[x < 0, Print["negative"], Print["zero"]]]	use Python execution control	use Python execution control	if x > 0 then print("positive") else if x < 0 then print("negative") else print("zero");
while	i = 0 While[i < 10, Print[i]; i++]			for i: 0 step 1 while i < 10 do print(i);
for	For[i = 0, i < 10, i++, Print[i]]			for i: 1 step 1 thru 10 do print(i);
break	Break[]
continue	Continue[]
exceptions
	mathematica	sympy	sage	maxima
raise exception	Throw["failed"]	use Python exceptions	use Python exceptions	error("failed");
handle exception	Print[Catch[Throw["failed"]]]			errcatch(error("failed"));
streams
	mathematica	sympy	sage	maxima
standard file handles	Streams["stdout"] Streams["stderr"] (* all open file handles: *) Streams[]
write line to stdout	Print["hello"]
open file for reading	f = OpenRead["/etc/hosts"]
open file for writing	f = OpenWrite["/tmp/test"]
open file for appending	f = OpenAppend["/tmp/test"]
close file	Close[f]
read file into string	s = ReadString[f]
write string	WriteString[f, "lorem ipsum"]
read file into array of strings	s = Import["/etc/hosts"] a = StringSplit[s, "\n"]
file handle position get, set	f = StringToStream["foo bar baz"] StreamPosition[f] (* beginning of stream: ) SetStreamPosition[f, 0] (# end of stream: ) SetStreamPosition[f, Infinity]
open temporary file	f = OpenWrite[] path = Part[f, 1]
files
	mathematica	sympy	sage	maxima
file exists test, regular file test	FileExistsQ["/etc/hosts"] FileType["/etc/hosts"] == File
file size	FileByteCount["/etc/hosts"]
is file readable, writable, executable
last modification time	FileDate["/etc/hosts"]
copy file, remove file, rename file	CopyFile["/tmp/foo", "/tmp/bar"] DeleteFile["/tmp/foo"] RenameFile["/tmp/bar", "/tmp/foo"]
directories
	mathematica	sympy	sage	maxima
working directory	dir = Directory[] SetDirectory["/tmp"]
build pathname	FileNameJoin[{"/etc", "hosts"}]
dirname and basename	DirectoryName["/etc/hosts"] FileBaseName["/etc/hosts"]
absolute pathname	(* file must exist; symbolic links are resolved: *) AbsoluteFileName["foo"] AbsoluteFileName["/foo"] AbsoluteFileName["../foo"] AbsoluteFileName["./foo"] AbsoluteFileName["~/foo"]
glob paths	Function[x, Print[x]] /@ FileNames["/tmp/*"]
make directory	CreateDirectory["/tmp/foo.d"]
recursive copy	CopyDirectory["/tmp/foo.d", "/tmp/baz.d"]
remove empty directory	DeleteDirectory["/tmp/foo.d"]
remove directory and contents	DeleteDirectory["/tmp/foo.d", DeleteContents -> True]
directory test	DirectoryQ["/etc"]
libraries and namespaces
	mathematica	sympy	sage	maxima
load library	Get["foo.m"]			load(grobner);
reflection
	mathematica	sympy	sage	maxima
get function documentation	?Tan Information[Tan]	print(solve.__doc__) # in IJupyter: solve? help(solve)	solve?	describe(solve); ? solve;
function options	Options[Solve] Options[Plot]
function source		import inspect inspect.getsourcelines(integrate)
query data type	Head[x]		type(x)	symbolp(x); numberp(7); stringp("seven"); listp([1, 2, 3]);
list variables in scope	Names[$Context <> "*"]			/* user defined variables: / values; / user defined functions: */ functions;
	____________________________________________________	____________________________________________________	____________________________________________________	____________________________________________________

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version used

The version of software used to check the examples in the reference sheet.

show version

How to determine the version of an installation.

implicit prologue

Code assumed to have been executed by the examples in the sheet.

Grammar and Invocation

interpreter

How to execute a script.

mathematica:

The full path to MathKernel on Mac OS X:

/Applications/Mathematica.app/Contents/MacOS/MathKernel

repl

How to launch a command line read-eval-print loop for the language.

end-of-line comment

Character used to start a comment that goes to the end of the line.

multiple line comment

The syntax for a delimited comment which can span lines.

Variables and Expressions

assignment

How to perform assignment.

Mathematica, Sympy, and Pari/GP support the chaining of assignments. For example, in Mathematica one can assign the value 3 to x and y with:

x = y = 3

In Mathematica and Pari/GP, assignments are expressions. In Mathematica, the following code is legal and evaluates to 7:

(x = 3) + 4

In Mathematica, the Set function behaves identically to assignment and can be nested:

Set[a, Set[b, 3]]

delayed assignment

How to assign an expression to a variable name. The expression is re-evaluated each time the variable is used.

mathematica:

GNU make also supports assignment and delayed assignment, but = is used for delayed assignment and := is used for immediate assignment. This is the opposite of how Mathematica uses the symbols.

The POSIX standard for make only has = for delayed assignment.

parallel assignment

How to assign values in parallel.

Parallel assignment can be used to swap the values held in two variables.

increment and decrement

Increment and decrement operators which can be used in expressions.

non-referential identifier

An identifier which does not refer to a value.

A non-referential identifier will usually print as a string containing its name.

Expressions containing non-referential identifiers will not be evaluated, though they may be simplified.

Non-referential identifiers represent "unknowns" or "parameters" when performing algebraic derivations.

identifier as value

How to get a value referring to an identifier.

The identifier may be the name of a variable containing a value. But the value referring to the identifier is distinct from the value in the variable.

One may manipulate a value referring to an identifier even if it is not the name of a variable.

local variable

How to declare a local variable.

pari/gp:

There is my for declaring a local variable with lexical scope and local for declaring a variable with dynamic scope.

local can be used to change the value of a global as seen by any functions which are called while the local scope is in effect.

undefined variable access

What happens when an undefined variable is used in an expression.

remove variable binding

How to remove a variable. Subsequent references to the variable will be treated as if the variable were undefined.

Arithmetic and Logic

falsehoods

Values which evaluate to false in a conditional test.

sympy:

Note that the logical operators Not, And and Or do not treat empty collections or None as false. This is different from the Python logical operators not, and, and or.

pari/gp:

A vector or matrix evaluates to false if all components evaluate to false.

logical operators

The Boolean operators.

sympy:

In Python, &, |, and & are bit operators. SymPy has defined __and__, __or__, and __invert__ methods to make them Boolean operators for symbols, however.

relational operators

The relational operators.

sympy:

The full SymPy names for the relational operators are:

sympy.Equality             # ==
sympy.Unequality           # !=
sympy.GreaterThan          # >=
sympy.LessThan             # <=
sympy.StrictGreaterThan    # >
sympy.StrictLessThan       # <

The SymPy functions are attatched to the relational operators ==, !=, for symbols … using the methods __eq__, __ne__, __ge__, __le__, __gt__, __lt__. The behavior they provide is similar to the default Python behavior, but when one of the arguments is a SymPy expression, a simplification will be attempted before the comparison is made.

arithmetic operators

The arithmetic operators.

integer division

How to compute the quotient of two integers.

integer division by zero

The result of dividing an integer by zero.

float division

How to perform float division, even if the arguments are integers.

float division by zero

The result of dividing a float by zero.

power

How to compute exponentiation.

Note that zero to a negative power is equivalent to division by zero, and negative numbers to a fractional power may have multiple complex solutions.

sqrt

The square root function.

For positive arguments the positive square root is returned.

sqrt -1

How the square root function handles negative arguments.

mathematica:

An uppercase I is used to enter the imaginary unit, but Mathematica displays it as a lowercase i.

transcendental functions

The standard transcendental functions such as one might find on a scientific calculator.

The functions are the exponential (not to be confused with exponentiation), natural logarithm, sine, cosine, tangent, arcsine, arccosine, arctangent, and the two argument arctangent.

transcendental constants

The transcendental constants pi and e.

The transcendental functions can used to computed to compute the transcendental constants:

pi = acos(-1)
pi = 4 * atan(1)
e = exp(1)

float truncation

Ways to convert a float to a nearby integer.

absolute value

How to get the absolute value and signum of a number.

integer overflow

What happens when the value of an integer expression cannot be stored in an integer.

The languages in this sheet all support arbitrary length integers so the situation does not happen.

float overflow

What happens when the value of a floating point expression cannot be stored in a float.

rational construction

How to construct a rational number.

rational decomposition

How to extract the numerator and denominator from a rational number.

decimal approximation

How to get a decimal approximation of an irrational number or repeating decimal rational.

complex construction

How to construct a complex number.

complex decomposition

How to extract the real and imaginary part from a complex number; how to extract the argument and modulus; how to get the complex conjugate.

random number

How to generate a random integer or a random float.

pari/gp:

When the argument of random() is an integer n, it generates an integer in the range $\{0, ..., n - 1\}$ .

When the argument is a arbitrary precision float, it generates a value in the range [0.0, 1.0]. The precision of the argument determines the precision of the random number.

random seed

How to set or get the random seed.

mathematica:

The seed is not set to the same value at start up.

bit operators

binary, octal, and hex literals

Binary, octal, and hex integer literals.

mathematica:

The notation works for any base from 2 to 36.

radix

Convert a number to a representation using a given radix.

to array of digits

Convert a number to an array of digits representing the number.

Strings

string literal

The syntax for a string literal.

newline in literal

Are newlines permitted in string literals.

literal escapes

Escape sequences for putting unusual characters in string literals.

concatenate

How to concatenate strings.

translate case

How to convert a string to all lower case letters or all upper case letters.

trim

How to remove whitespace from the beginning or the end of string.

number to string

How to convert a number to a string.

string to number

How to parse a number from a string.

string join

How to join an array of strings into a single string, possibly separated by a delimiter.

split

How to split a string in to an array of strings. How to specify the delimiter.

substitute

How to substitute one or all occurrences of substring with another.

length

How to get the length of a string in characters.

index of substring

How to get the index of the first occurrence of a substring.

extract substring

How to get a substring from a string using character indices.

character literal

The syntax for a character literal.

character lookup

How to get a character from a string by index.

chr and ord

Convert a character code point to a character or a single character string.

Get the character code point for a character or single character string.

delete characters

Delete all occurrences of a set of characters from a string.

Arrays

section	mathematica	maple	maxima	sympy
arrays	List	list	list	list
multidimensional arrays	List	Array	array	none
vectors	List	Vector	list	Matrix
matrices	List	Matrix	matrix	Matrix

literal

The notation for an array literal.

size

The number of elements in the array.

lookup

How to access an array element by its index.

update

How to change the value stored at an array index.

out-of-bounds behavior

What happens when an attempt is made to access an element at an out-of-bounds index.

element index

How to get the index of an element in an array.

slice

How to extract a subset of the elements. The indices for the elements must be contiguous.

array of integers as index

manipulate back

manipulate front

head

tail

cons

concatenate

replicate

copy

How to copy an array. Updating the copy will not alter the original.

iterate

reverse

sort

dedupe

membership

How to test whether a value is an element of a list.

intersection

How to to find the intersection of two lists.

union

How to find the union of two lists.

relative complement, symmetric difference

How to find all elements in one list which are not in another; how to find all elements which are in one of two lists but not both.

map

filter

reduce

universal and existential tests

min and max element

shuffle and sample

How to shuffle an array. How to extract a random sample from an array without replacement.

flatten

zip

How to interleave two arrays.

cartesian product

Sets

Arithmetic Sequences

Dictionaries

record literal

record member access

Functions

definition

invocation

function value

Execution Control

if

How to write a branch statement.

mathematica:

The 3rd argument (the else clause) of an If expression is optional.

while

How to write a conditional loop.

mathematica:

Do can be used for a finite unconditional loop:

Do[Print[foo], {10}]

for

How to write a C-style for statement.

break/continue

How to break out of a loop. How to jump to the next iteration of a loop.

Exceptions

raise exception

How to raise an exception.

handle exception

How to handle an exception.

uncaught exception behavior

gap:

Calling Error() invokes the GAP debugger, which is similar to a Lisp debugger. In particular, all the commands available in the GAP REPL are still available. Variables can be inspected and modified while in the debugger but any changes will be lost when the debugger is quitted.

One uses quit; or ^D to exit the debugger. These commands also cause the top-level GAP REPL exit if used while not in a debugger.

If Error() is invoked while in the GAP debugger, the debugger will be invoked recursively. One must use quit; for each level of debugger recursion to return to the top -level GAP REPL.

Use

brk> Where(4);

to print the top four functions on the stack when the error occurred. Use DownEnv() and UpEnv() to move down the stack—i.e. from callee to caller—and UpEnv() to move up the stack. The commands take the number of levels to move down or up:

brk> DownEnv(2);
brk> UpEnv(2);

When the debugger is invoked, it will print a message. It may give the user the option of providing a value with the return statement so that a computation can be continued:

brk> return 17;

record literal

record member access

definition

invocation

function value

if

while

for

break/continue

finally block

function documentation