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Head[expr]

gives the head of expr.

Head[expr,h]

wraps the result with h.

Examples  
Basic Examples  
Scope  
Applications  
Properties & Relations  
Possible Issues  
Neat Examples  
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Head

Head[expr]

gives the head of expr.

Head[expr,h]

wraps the result with h.

Examples

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Basic Examples  (3)

The head of a function:

Wolfram Language code: Head[f[a, b]]

The head of a list:

Wolfram Language code: Head[{a, b, c}]

The heads of atomic expressions:

Wolfram Language code: Head[45]
Wolfram Language code: Head[x]

Scope  (3)

The head of a function entered with an operator:

Wolfram Language code: Head[a + b + c]

The head of a compound expression:

Wolfram Language code: Head[f[x][y][z]]

Wrap the result in Hold to prevent the result from evaluating:

Wolfram Language code: Head[Unevaluated[InverseFunction[Sin][1]], Hold]

Without the second argument, the InverseFunction expression would evaluate:

Wolfram Language code: Head[Unevaluated[InverseFunction[Sin][1]]]

Applications  (2)

Find the cases with a head of Integer:

Wolfram Language code: Cases[{2, 1, x, 3, y}, _Integer]

Verify the result:

Wolfram Language code: Head /@ %

Define a function that extracts the head and guarantees no evaluation occurs:

Wolfram Language code: SetAttributes[safeHead, HoldAllComplete] safeHead[e_] := Head[Unevaluated[e], HoldComplete]
Wolfram Language code: safeHead[Cos'[x]]

Without the HoldComplete, a Function object would be returned:

Wolfram Language code: %//ReleaseHold

Properties & Relations  (2)

The head is the part with index 0:

Wolfram Language code: (a + b + c)[[0]]

Head[e,f] is effectively equivalent to Extract[e,0,f]:

Wolfram Language code: Head[{1, 2, 3}, f]
Wolfram Language code: Extract[{1, 2, 3}, 0, f]

Possible Issues  (1)

The head is based on FullForm:

Wolfram Language code: Head[a / b]
Wolfram Language code: FullForm[a / b]

Neat Examples  (1)

Head always eventually burrows to a symbol:

Wolfram Language code: FixedPoint[Head, f[x][y][z]]
Wolfram Language code: FixedPoint[Head, {3, 4, 5}]
Wolfram Research (1988), Head, Wolfram Language function, https://reference.wolfram.com/language/ref/Head.html (updated 2020).

Text

Wolfram Research (1988), Head, Wolfram Language function, https://reference.wolfram.com/language/ref/Head.html (updated 2020).

CMS

Wolfram Language. 1988. "Head." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/Head.html.

APA

Wolfram Language. (1988). Head. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Head.html

BibTeX

@misc{reference.wolfram_2026_head, author="Wolfram Research", title="{Head}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/Head.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_head, organization={Wolfram Research}, title={Head}, year={2020}, url={https://reference.wolfram.com/language/ref/Head.html}, note=[Accessed: 12-June-2026]}