Min and Max of a list of Associations

up vote
10
down vote

favorite

I am trying to find the minimum values for all elements in a list of associations, below is an example

x = "a"->12, "b"->3, "c"->21

Required output for Min
<

Required output for Max
"a"-> 21, "b"->11, "c"->15

My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1

for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15

Is there an elegant way to achieve this result?

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

1

I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30

add a comment |

up vote
10
down vote

favorite

I am trying to find the minimum values for all elements in a list of associations, below is an example

x = "a"->12, "b"->3, "c"->21

Required output for Min
<

Required output for Max
"a"-> 21, "b"->11, "c"->15

My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1

for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15

Is there an elegant way to achieve this result?

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

1

I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30

add a comment |

up vote
10
down vote

favorite

I am trying to find the minimum values for all elements in a list of associations, below is an example

x = "a"->12, "b"->3, "c"->21

Required output for Min
<

Required output for Max
"a"-> 21, "b"->11, "c"->15

My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1

for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15

Is there an elegant way to achieve this result?

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

I am trying to find the minimum values for all elements in a list of associations, below is an example

x = "a"->12, "b"->3, "c"->21

Required output for Min
<

Required output for Max
"a"-> 21, "b"->11, "c"->15

My attempt
for Max: MaximalBy[Values]@x
Result: "a" -> 21, "b" -> 11, "c" -> 1

for Min: MinimalBy[Values]@x
Result: "a" -> 4, "b" -> 9, "c" -> 15

Is there an elegant way to achieve this result?

list-manipulation associations

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

edited Dec 7 at 6:22

C. E.

49.4k395200

edited Dec 7 at 6:22

C. E.

49.4k395200

edited Dec 7 at 6:22

C. E.

49.4k395200

asked Dec 7 at 5:39

Professor Williams

533

asked Dec 7 at 5:39

Professor Williams

533

asked Dec 7 at 5:39

Professor Williams

533

1

I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30

add a comment |

1

I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30

I don't get it. How is the key a getting the value 2? That value does not appear for a in any of the associations. Similarly, why is the value of c not equal to 21 in the maximal result?
– Shredderroy
Dec 7 at 6:30

add a comment |

3 Answers
3

active

oldest

votes

up vote
13
down vote

accepted

How about

a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)

EDIT

Improved, as per Kuba's suggestion.

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

add a comment |

up vote
6
down vote

Random`Private`MapThreadMin[x]
Random`Private`MapThreadMax[x]

<|"a" -> 4, "b" -> 3, "c" -> 1|>

<|"a" -> 21, "b" -> 11, "c" -> 21|>

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

1

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

1

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

add a comment |

up vote
1
down vote

You may use Query and MinMax.

With x as in OP.

Query[Transpose /* Map[MinMax]]@x

<|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>

You can produce a more descriptive result with AssociationThread.

res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x

<|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
 "c" -> <|"Min" -> 1, "Max" -> 21|>|>

Which you can then access by Key with Association's syntax sugar.

res["a", "Max"]

Hope this helps.

answered Dec 7 at 10:30

Edmund

25.5k330100

add a comment |

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

up vote
13
down vote

accepted

How about

a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)

EDIT

Improved, as per Kuba's suggestion.

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

add a comment |

up vote
13
down vote

accepted

How about

a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)

EDIT

Improved, as per Kuba's suggestion.

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

add a comment |

up vote
13
down vote

accepted

How about

a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)

EDIT

Improved, as per Kuba's suggestion.

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

How about

a = >,
 <;

Merge[a, Min]

(*<|"a" -> 4, "b" -> 3, "c" -> 1|>*)

Merge[a, Max]

(*<|"a" -> 21, "b" -> 11, "c" -> 21|>*)

EDIT

Improved, as per Kuba's suggestion.

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

edited Dec 7 at 8:30

answered Dec 7 at 6:22

Shredderroy

1,4931115

answered Dec 7 at 6:22

Shredderroy

1,4931115

answered Dec 7 at 6:22

Shredderroy

1,4931115

add a comment |

up vote
6
down vote

Random`Private`MapThreadMin[x]
Random`Private`MapThreadMax[x]

<|"a" -> 4, "b" -> 3, "c" -> 1|>

<|"a" -> 21, "b" -> 11, "c" -> 21|>

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

1

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

1

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

add a comment |

up vote
6
down vote

Random`Private`MapThreadMin[x]
Random`Private`MapThreadMax[x]

<|"a" -> 4, "b" -> 3, "c" -> 1|>

<|"a" -> 21, "b" -> 11, "c" -> 21|>

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

1

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

1

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

add a comment |

up vote
6
down vote

Random`Private`MapThreadMin[x]
Random`Private`MapThreadMax[x]

<|"a" -> 4, "b" -> 3, "c" -> 1|>

<|"a" -> 21, "b" -> 11, "c" -> 21|>

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

Random`Private`MapThreadMin[x]
Random`Private`MapThreadMax[x]

<|"a" -> 4, "b" -> 3, "c" -> 1|>

<|"a" -> 21, "b" -> 11, "c" -> 21|>

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

answered Dec 7 at 6:34

Henrik Schumacher

47.6k466134

1

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

1

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

add a comment |

1

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

1

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

is there any list out there for these "hidden" commands? Or do you happen to have a favourite list that you can share with us?
– Soner
Dec 7 at 12:33

A good try is always ?**` ;) Honestly, I learned this trick very recently from Carl Woll. Some other good place to look for such things is What are some useful undocumented Mathematica functions?
– Henrik Schumacher
Dec 7 at 13:45

Thanks, I am checking the link right now :)
– Soner
Dec 7 at 21:35

add a comment |

up vote
1
down vote

You may use Query and MinMax.

With x as in OP.

Query[Transpose /* Map[MinMax]]@x

<|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>

You can produce a more descriptive result with AssociationThread.

res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x

<|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
 "c" -> <|"Min" -> 1, "Max" -> 21|>|>

Which you can then access by Key with Association's syntax sugar.

res["a", "Max"]

Hope this helps.

answered Dec 7 at 10:30

Edmund

25.5k330100

add a comment |

up vote
1
down vote

You may use Query and MinMax.

With x as in OP.

Query[Transpose /* Map[MinMax]]@x

<|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>

You can produce a more descriptive result with AssociationThread.

res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x

<|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
 "c" -> <|"Min" -> 1, "Max" -> 21|>|>

Which you can then access by Key with Association's syntax sugar.

res["a", "Max"]

Hope this helps.

answered Dec 7 at 10:30

Edmund

25.5k330100

add a comment |

up vote
1
down vote

You may use Query and MinMax.

With x as in OP.

Query[Transpose /* Map[MinMax]]@x

<|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>

You can produce a more descriptive result with AssociationThread.

res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x

<|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
 "c" -> <|"Min" -> 1, "Max" -> 21|>|>

Which you can then access by Key with Association's syntax sugar.

res["a", "Max"]

Hope this helps.

answered Dec 7 at 10:30

Edmund

25.5k330100

You may use Query and MinMax.

With x as in OP.

Query[Transpose /* Map[MinMax]]@x

<|"a" -> 4, 21, "b" -> 3, 11, "c" -> 1, 21|>

You can produce a more descriptive result with AssociationThread.

res = Query[Transpose /* Map[AssociationThread["Min", "Max", MinMax@#] &]]@x

<|"a" -> <|"Min" -> 4, "Max" -> 21|>, 
 "b" -> <|"Min" -> 3, "Max" -> 11|>, 
 "c" -> <|"Min" -> 1, "Max" -> 21|>|>

Which you can then access by Key with Association's syntax sugar.

res["a", "Max"]

Hope this helps.

answered Dec 7 at 10:30

Edmund

25.5k330100

answered Dec 7 at 10:30

Edmund

25.5k330100

answered Dec 7 at 10:30

Edmund

25.5k330100

answered Dec 7 at 10:30

Edmund

25.5k330100

add a comment |

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