symFunType

Determine functional type of symbolic object

Syntax

s = symFunType(symObj)

Description

example

s = symFunType(symObj) returns the functional type of a symbolic object.

  • If symObj is a symbolic function or a symbolic expression, then symFunType returns the topmost function name or operator of symObj. For example, syms x; symFunType(2*sin(x)) returns "times".

  • If symObj is not a symbolic function or a symbolic expression, then symFunType returns the same output as symType. For example, symFunType(sym('2')) returns "integer".

Examples

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Create an array of symbolic functions and expressions.

syms f(x)
expr = [f(x) sin(x) exp(x) int(f(x)) diff(f(x))]
expr = 

(f(x)sin(x)exf(x)dxx f(x))

Determine the functional type of each array element.

s = symFunType(expr)
s = 1x5 string array
    "f"    "sin"    "exp"    "int"    "diff"

Create two symbolic expressions. Determine the topmost arithmetic operators of the expressions.

syms x
expr1 = x/(x^2+x+2);
expr2 = x + 1/(x^2+x+2);
s1 = symFunType(expr1)
s1 = 
"times"
s2 = symFunType(expr2)
s2 = 
"plus"

To return the terms separated by the operators, use children.

terms1 = children(expr1)
terms1 = 

(x1x2+x+2)

terms2 = children(expr2)
terms2 = 

(x1x2+x+2)

Create an array of symbolic equations and inequalities.

syms x y
eqns = [x+y==2, x<=5, y>3]
eqns = (x+y=2x53<y)

Determine the topmost comparison operator in each array element.

s = symFunType(eqns)
s = 1x3 string array
    "eq"    "le"    "lt"

Input Arguments

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Symbolic objects, specified as symbolic expressions, symbolic functions, symbolic variables, symbolic numbers, or symbolic units.

Output Arguments

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Symbolic functional types, returned as a string array. If symObj is a symbolic function or a symbolic expression, then symFunType returns the topmost function name or operator of symObj. This table shows output values for various symbolic objects.

Symbolic Functional TypesReturned OutputInput Example
symbolic math functions"sin", "exp", "fourier", and so on — name of the topmost symbolic math function in a symbolic expressionsyms f(x); symFunType([sin(x), exp(x), fourier(x)])
unassigned symbolic functions

"f", "g", and so on — unassigned symbolic function

syms f(x) g(x); symFunType([f, g(x+2)])
arithmetic operators
  • "plus" — addition operator + and subtraction operator -

  • "times" — multiplication operator * and division operator /

  • "power" — power or exponentiation operator ^ and square root operator sqrt

  • syms x; symFunType(x^2-x)

  • syms x; symFunType(2*x^2)

  • syms x; symFunType([x^2 sqrt(x)])

equations and inequalities
  • "eq" — equality operator ==

  • "ne" — inequality operator ~=

  • "lt" — less-than operator < or greater-than operator >

  • "le" — less-than-or-equal-to operator <= or greater-than-or-equal-to operator >=

  • syms x y; symFunType(x==y)

  • syms x y; symFunType(x~=y)

  • syms x y; symFunType(x<y)

  • syms x y; symFunType(x>=y)

logical operators
  • "or" — logical OR operator |

  • "and" — logical AND operator &

  • "not" — logical NOT operator ~

  • "xor" — logical exclusive-OR operator xor

  • syms x y; symFunType(x|y)

  • syms x y; symFunType(x&y)

  • syms x; symFunType(~x)

  • syms x y; symFunType(xor(x,y))

numbers
  • "integer" — integer number

  • "rational" — rational number

  • "vpareal" — variable-precision floating-point real number

  • "complex" — complex number

  • symFunType(sym('-1'))

  • symFunType(sym('1/2'))

  • symFunType([sym('1.5') vpa('3/2')])

  • symFunType(sym('1+2i'))

constants

"constant"

symFunType(sym([pi catalan]))
variables

"variable"

symFunType(sym(x))
units

"units"

symFunType(symunit('m'))
unsupported symbolic types"unsupported" 

Introduced in R2019a