How to extract the argument from an in-built function
up vote
1
down vote
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I would like to extract the argument from :
DiracDelta[-10 + x + ξ]
extract
asked 1 hour ago
Riccardo
185
add a comment |
up vote
1
down vote
favorite
I would like to extract the argument from :
DiracDelta[-10 + x + ξ]
extract
asked 1 hour ago
Riccardo
185
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I would like to extract the argument from :
DiracDelta[-10 + x + ξ]
extract
asked 1 hour ago
Riccardo
185
I would like to extract the argument from :
DiracDelta[-10 + x + ξ]
extract
extract
asked 1 hour ago
Riccardo
185
asked 1 hour ago
Riccardo
185
edited 8 mins ago
asked 1 hour ago
Riccardo
185
asked 1 hour ago
Riccardo
185
asked 1 hour ago
Riccardo
185
185
add a comment |
add a comment |
2 Answers
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votes
up vote
4
down vote
You can use Part to access the parts of any normal expression.
DiracDelta[-10 + x + ξ][[1]]
(* -10 + x + ξ *)
In this case you can also use First since you want the first part.
Another common need is to pull out the arguments of a function when that function is buried in a larger expression. For this you can use Cases
Cases[
{w''[z] + k^2 w[z] == DiracDelta[z], w[0] == 0, w'[0] == 1},
DiracDelta[arg_] :> arg, Infinity]
(* {z} *)
answered 1 hour ago
Jason B.
47.6k387185
add a comment |
up vote
1
down vote
DiracDelta[-10 + x + [Xi]] /. DiracDelta -> " "
or (as @JasonB wrote):
First@DiracDelta[-10 + x + [Xi]]
answered 49 mins ago
David G. Stork
22.9k22051
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
You can use Part to access the parts of any normal expression.
DiracDelta[-10 + x + ξ][[1]]
(* -10 + x + ξ *)
In this case you can also use First since you want the first part.
Another common need is to pull out the arguments of a function when that function is buried in a larger expression. For this you can use Cases
Cases[
{w''[z] + k^2 w[z] == DiracDelta[z], w[0] == 0, w'[0] == 1},
DiracDelta[arg_] :> arg, Infinity]
(* {z} *)
answered 1 hour ago
Jason B.
47.6k387185
add a comment |
up vote
4
down vote
You can use Part to access the parts of any normal expression.
DiracDelta[-10 + x + ξ][[1]]
(* -10 + x + ξ *)
In this case you can also use First since you want the first part.
Another common need is to pull out the arguments of a function when that function is buried in a larger expression. For this you can use Cases
Cases[
{w''[z] + k^2 w[z] == DiracDelta[z], w[0] == 0, w'[0] == 1},
DiracDelta[arg_] :> arg, Infinity]
(* {z} *)
answered 1 hour ago
Jason B.
47.6k387185
add a comment |
up vote
4
down vote
up vote
4
down vote
You can use Part to access the parts of any normal expression.
DiracDelta[-10 + x + ξ][[1]]
(* -10 + x + ξ *)
In this case you can also use First since you want the first part.
Another common need is to pull out the arguments of a function when that function is buried in a larger expression. For this you can use Cases
Cases[
{w''[z] + k^2 w[z] == DiracDelta[z], w[0] == 0, w'[0] == 1},
DiracDelta[arg_] :> arg, Infinity]
(* {z} *)
answered 1 hour ago
Jason B.
47.6k387185
You can use Part to access the parts of any normal expression.
DiracDelta[-10 + x + ξ][[1]]
(* -10 + x + ξ *)
In this case you can also use First since you want the first part.
Another common need is to pull out the arguments of a function when that function is buried in a larger expression. For this you can use Cases
Cases[
{w''[z] + k^2 w[z] == DiracDelta[z], w[0] == 0, w'[0] == 1},
DiracDelta[arg_] :> arg, Infinity]
(* {z} *)
answered 1 hour ago
Jason B.
47.6k387185
edited 15 mins ago
answered 1 hour ago
Jason B.
47.6k387185
answered 1 hour ago
Jason B.
47.6k387185
answered 1 hour ago
Jason B.
47.6k387185
47.6k387185
add a comment |
add a comment |
up vote
1
down vote
DiracDelta[-10 + x + [Xi]] /. DiracDelta -> " "
or (as @JasonB wrote):
First@DiracDelta[-10 + x + [Xi]]
answered 49 mins ago
David G. Stork
22.9k22051
add a comment |
up vote
1
down vote
DiracDelta[-10 + x + [Xi]] /. DiracDelta -> " "
or (as @JasonB wrote):
First@DiracDelta[-10 + x + [Xi]]
answered 49 mins ago
David G. Stork
22.9k22051
add a comment |
up vote
1
down vote
up vote
1
down vote
DiracDelta[-10 + x + [Xi]] /. DiracDelta -> " "
or (as @JasonB wrote):
First@DiracDelta[-10 + x + [Xi]]
answered 49 mins ago
David G. Stork
22.9k22051
DiracDelta[-10 + x + [Xi]] /. DiracDelta -> " "
or (as @JasonB wrote):
First@DiracDelta[-10 + x + [Xi]]
answered 49 mins ago
David G. Stork
22.9k22051
answered 49 mins ago
David G. Stork
22.9k22051
answered 49 mins ago
David G. Stork
22.9k22051
answered 49 mins ago
David G. Stork
22.9k22051
22.9k22051
add a comment |
add a comment |
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