Pattern matching list of lists containing only numbers

up vote
4
down vote

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I'm trying to define a pattern that will match lists of lists, where the inner lists contains only numbers (I want the sum of each list). Like this

1, 2, 3, 4

But not like this

1, 1, 3,3

Why this is not working?

Clear[foo];
foo[x : v___List] := Plus @@@ x /; VectorQ[v, NumberQ]

Thank you!

asked Aug 21 at 19:43

Fernando

1233

your condition VectorQ[v, NumberQ] for v=Sequence[1, 2, 3, 4] becomes VectorQ[1, 2, 3, 4, NumberQ] thus you get the error message VectorQ::argt: VectorQ called with **3** arguments; 1 or 2 arguments are expected.
â€“Â kglr
Aug 21 at 20:00

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up vote
4
down vote

favorite

I'm trying to define a pattern that will match lists of lists, where the inner lists contains only numbers (I want the sum of each list). Like this

1, 2, 3, 4

But not like this

1, 1, 3,3

Why this is not working?

Clear[foo];
foo[x : v___List] := Plus @@@ x /; VectorQ[v, NumberQ]

Thank you!

asked Aug 21 at 19:43

Fernando

1233

your condition VectorQ[v, NumberQ] for v=Sequence[1, 2, 3, 4] becomes VectorQ[1, 2, 3, 4, NumberQ] thus you get the error message VectorQ::argt: VectorQ called with **3** arguments; 1 or 2 arguments are expected.
â€“Â kglr
Aug 21 at 20:00

add a commentÂ |Â

up vote
4
down vote

favorite

I'm trying to define a pattern that will match lists of lists, where the inner lists contains only numbers (I want the sum of each list). Like this

1, 2, 3, 4

But not like this

1, 1, 3,3

Why this is not working?

Clear[foo];
foo[x : v___List] := Plus @@@ x /; VectorQ[v, NumberQ]

Thank you!

asked Aug 21 at 19:43

Fernando

1233

I'm trying to define a pattern that will match lists of lists, where the inner lists contains only numbers (I want the sum of each list). Like this

1, 2, 3, 4

But not like this

1, 1, 3,3

Why this is not working?

Clear[foo];
foo[x : v___List] := Plus @@@ x /; VectorQ[v, NumberQ]

Thank you!

asked Aug 21 at 19:43

Fernando

1233

asked Aug 21 at 19:43

Fernando

1233

asked Aug 21 at 19:43

Fernando

1233

asked Aug 21 at 19:43

Fernando

1233

your condition VectorQ[v, NumberQ] for v=Sequence[1, 2, 3, 4] becomes VectorQ[1, 2, 3, 4, NumberQ] thus you get the error message VectorQ::argt: VectorQ called with **3** arguments; 1 or 2 arguments are expected.
â€“Â kglr
Aug 21 at 20:00

add a commentÂ |Â

your condition VectorQ[v, NumberQ] for v=Sequence[1, 2, 3, 4] becomes VectorQ[1, 2, 3, 4, NumberQ] thus you get the error message VectorQ::argt: VectorQ called with **3** arguments; 1 or 2 arguments are expected.
â€“Â kglr
Aug 21 at 20:00

your condition VectorQ[v, NumberQ] for v=Sequence[1, 2, 3, 4] becomes VectorQ[1, 2, 3, 4, NumberQ] thus you get the error message VectorQ::argt: VectorQ called with **3** arguments; 1 or 2 arguments are expected.
â€“Â kglr
Aug 21 at 20:00

add a commentÂ |Â

2 Answers
2

active

oldest

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up vote
6
down vote

accepted

ClearAll[foo];
foo[x : ___List?(VectorQ[#, NumberQ] &)] := Plus @@@ x

foo[1, 2, 2, 3, 4]

3, 9

foo[1, 2, 3]

foo[1, 2, 3]

Note: You need to use NumericQ in place of NumberQ if you want foo[1, 2, 2, 3, ÃÂ€] to return 3, 2 + 3 ÃÂ€.

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

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up vote
4
down vote

Another approach is to use Total, with a condition to forbid it from totaling entries with a single term:

f[x_] := If[Length[x] > 1, Total[x], x]

For instance:

f /@ 1, 2, 2, 3, 4
3, 9
f /@ 1, 2, 2, 3, 4, 3
3, 9, 3

answered Aug 21 at 21:27

bill s

50.6k373142

add a commentÂ |Â

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
6
down vote

accepted

ClearAll[foo];
foo[x : ___List?(VectorQ[#, NumberQ] &)] := Plus @@@ x

foo[1, 2, 2, 3, 4]

3, 9

foo[1, 2, 3]

foo[1, 2, 3]

Note: You need to use NumericQ in place of NumberQ if you want foo[1, 2, 2, 3, ÃÂ€] to return 3, 2 + 3 ÃÂ€.

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

add a commentÂ |Â

up vote
6
down vote

accepted

ClearAll[foo];
foo[x : ___List?(VectorQ[#, NumberQ] &)] := Plus @@@ x

foo[1, 2, 2, 3, 4]

3, 9

foo[1, 2, 3]

foo[1, 2, 3]

Note: You need to use NumericQ in place of NumberQ if you want foo[1, 2, 2, 3, ÃÂ€] to return 3, 2 + 3 ÃÂ€.

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

add a commentÂ |Â

up vote
6
down vote

accepted

ClearAll[foo];
foo[x : ___List?(VectorQ[#, NumberQ] &)] := Plus @@@ x

foo[1, 2, 2, 3, 4]

3, 9

foo[1, 2, 3]

foo[1, 2, 3]

Note: You need to use NumericQ in place of NumberQ if you want foo[1, 2, 2, 3, ÃÂ€] to return 3, 2 + 3 ÃÂ€.

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

ClearAll[foo];
foo[x : ___List?(VectorQ[#, NumberQ] &)] := Plus @@@ x

foo[1, 2, 2, 3, 4]

3, 9

foo[1, 2, 3]

foo[1, 2, 3]

Note: You need to use NumericQ in place of NumberQ if you want foo[1, 2, 2, 3, ÃÂ€] to return 3, 2 + 3 ÃÂ€.

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

edited Aug 21 at 20:05

answered Aug 21 at 19:57

kglr

158k8183380

answered Aug 21 at 19:57

kglr

158k8183380

answered Aug 21 at 19:57

kglr

158k8183380

add a commentÂ |Â

up vote
4
down vote

Another approach is to use Total, with a condition to forbid it from totaling entries with a single term:

f[x_] := If[Length[x] > 1, Total[x], x]

For instance:

f /@ 1, 2, 2, 3, 4
3, 9
f /@ 1, 2, 2, 3, 4, 3
3, 9, 3

answered Aug 21 at 21:27

bill s

50.6k373142

add a commentÂ |Â

up vote
4
down vote

Another approach is to use Total, with a condition to forbid it from totaling entries with a single term:

f[x_] := If[Length[x] > 1, Total[x], x]

For instance:

f /@ 1, 2, 2, 3, 4
3, 9
f /@ 1, 2, 2, 3, 4, 3
3, 9, 3

answered Aug 21 at 21:27

bill s

50.6k373142

add a commentÂ |Â

up vote
4
down vote

Another approach is to use Total, with a condition to forbid it from totaling entries with a single term:

f[x_] := If[Length[x] > 1, Total[x], x]

For instance:

f /@ 1, 2, 2, 3, 4
3, 9
f /@ 1, 2, 2, 3, 4, 3
3, 9, 3

answered Aug 21 at 21:27

bill s

50.6k373142

Another approach is to use Total, with a condition to forbid it from totaling entries with a single term:

f[x_] := If[Length[x] > 1, Total[x], x]

For instance:

f /@ 1, 2, 2, 3, 4
3, 9
f /@ 1, 2, 2, 3, 4, 3
3, 9, 3

answered Aug 21 at 21:27

bill s

50.6k373142

answered Aug 21 at 21:27

bill s

50.6k373142

answered Aug 21 at 21:27

bill s

50.6k373142

answered Aug 21 at 21:27

bill s

50.6k373142

add a commentÂ |Â

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