Revisions to Variable assignment to a function

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edited Apr 13, 2017 at 12:56

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

Beware that if x or y are defined before the Set this will fail. For a solution see:

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

Beware that if x or y are defined before the Set this will fail. For a solution see:

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

Beware that if x or y are defined before the Set this will fail. For a solution see:

added 148 characters in body

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edited Dec 23, 2016 at 19:18

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

Beware that if x or y are defined before the Set this will fail. For a solution see:

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

Beware that if x or y are defined before the Set this will fail. For a solution see:

Source Link

created Dec 14, 2016 at 17:20

You want to use Set rather than SetDelayed

Clear[f]

f[x_, y_] := x + 3 y /. {x -> -x y}

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> (x + 3 y /. {x -> -x y})}  *)

Trace will show you the evaluation sequence

f[1, 2] // Trace

Clear[f]

f[x_, y_] = x + 3 y /. {x -> -x y}

(*  3 y - x y  *)

DownValues[f]

(*  {HoldPattern[f[x_, y_]] :> 3 y - x y}  *)

f[1, 2] // Trace

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