Iterate over keys of association
How do you iterate over the keys or rules of an association (in any order)? E.g. for
<|"0"->"a", "1"->"b", "2"->"c"|>
I would like to either iterate over "0", "1", "2" or tuples containing each key and value.
For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).
associations
asked Dec 5 at 19:15
SLesslyTall
22317
add a comment |
How do you iterate over the keys or rules of an association (in any order)? E.g. for
<|"0"->"a", "1"->"b", "2"->"c"|>
I would like to either iterate over "0", "1", "2" or tuples containing each key and value.
For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).
associations
asked Dec 5 at 19:15
SLesslyTall
22317
1
Simply useMap,KeyValueMaporKeyMap?
– Henrik Schumacher
Dec 5 at 19:20
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
@SLesslyTall You see, you wantKeyValueMap[List] @ assobut who could've known :)
– Kuba♦
Dec 6 at 7:53
add a comment |
How do you iterate over the keys or rules of an association (in any order)? E.g. for
<|"0"->"a", "1"->"b", "2"->"c"|>
I would like to either iterate over "0", "1", "2" or tuples containing each key and value.
For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).
associations
asked Dec 5 at 19:15
SLesslyTall
22317
How do you iterate over the keys or rules of an association (in any order)? E.g. for
<|"0"->"a", "1"->"b", "2"->"c"|>
I would like to either iterate over "0", "1", "2" or tuples containing each key and value.
For example, something that performed the equivalent of a python dictionary's items, method would be ideal (which returns a list (or iterator) in the form [(key1, value1), ...], so {{"0", "a"}, {"1", "b"}, {"2", "c"}} here).
associations
associations
asked Dec 5 at 19:15
SLesslyTall
22317
asked Dec 5 at 19:15
SLesslyTall
22317
edited Dec 6 at 7:40
asked Dec 5 at 19:15
SLesslyTall
22317
asked Dec 5 at 19:15
SLesslyTall
22317
asked Dec 5 at 19:15
SLesslyTall
22317
22317
1
Simply useMap,KeyValueMaporKeyMap?
– Henrik Schumacher
Dec 5 at 19:20
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
@SLesslyTall You see, you wantKeyValueMap[List] @ assobut who could've known :)
– Kuba♦
Dec 6 at 7:53
add a comment |
1
Simply useMap,KeyValueMaporKeyMap?
– Henrik Schumacher
Dec 5 at 19:20
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
@SLesslyTall You see, you wantKeyValueMap[List] @ assobut who could've known :)
– Kuba♦
Dec 6 at 7:53
1
1
Simply use
Map, KeyValueMap or KeyMap?– Henrik Schumacher
Dec 5 at 19:20
Simply use
Map, KeyValueMap or KeyMap?– Henrik Schumacher
Dec 5 at 19:20
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
@SLesslyTall You see, you want
KeyValueMap[List] @ asso but who could've known :)– Kuba♦
Dec 6 at 7:53
@SLesslyTall You see, you want
KeyValueMap[List] @ asso but who could've known :)– Kuba♦
Dec 6 at 7:53
add a comment |
2 Answers
2
active
oldest
votes
To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):
In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
In[17]:= Do[Print[x], {x, Keys[assoc]}]
During evaluation of In[17]:= 0
During evaluation of In[17]:= 1
During evaluation of In[17]:= 2
answered Dec 5 at 19:41
Jason B.
47.7k387186
add a comment |
If you would like to map over the keys to transform them into something else, you can use KeyMap:
a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
a // KeyMap[("newKey" <> #) &]
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)
Otherwise, the good old Map will iterate over the values as if the structure were a list:
a // Map[("newVal" <> ToString@#) &]
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)
You should also look up KeyValueMap to see if that would make your task easier.
Edit
Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.
answered Dec 5 at 19:25
Shredderroy
1,4931115
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
To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):
In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
In[17]:= Do[Print[x], {x, Keys[assoc]}]
During evaluation of In[17]:= 0
During evaluation of In[17]:= 1
During evaluation of In[17]:= 2
answered Dec 5 at 19:41
Jason B.
47.7k387186
add a comment |
To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):
In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
In[17]:= Do[Print[x], {x, Keys[assoc]}]
During evaluation of In[17]:= 0
During evaluation of In[17]:= 1
During evaluation of In[17]:= 2
answered Dec 5 at 19:41
Jason B.
47.7k387186
add a comment |
To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):
In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
In[17]:= Do[Print[x], {x, Keys[assoc]}]
During evaluation of In[17]:= 0
During evaluation of In[17]:= 1
During evaluation of In[17]:= 2
answered Dec 5 at 19:41
Jason B.
47.7k387186
To iterate over the keys of an association, first get the keys in a list using Keys. then use this in your favorite iteration construct (Do, Table, Scan, Map, etc):
In[16]:= assoc = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
In[17]:= Do[Print[x], {x, Keys[assoc]}]
During evaluation of In[17]:= 0
During evaluation of In[17]:= 1
During evaluation of In[17]:= 2
answered Dec 5 at 19:41
Jason B.
47.7k387186
answered Dec 5 at 19:41
Jason B.
47.7k387186
answered Dec 5 at 19:41
Jason B.
47.7k387186
answered Dec 5 at 19:41
Jason B.
47.7k387186
47.7k387186
add a comment |
add a comment |
If you would like to map over the keys to transform them into something else, you can use KeyMap:
a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
a // KeyMap[("newKey" <> #) &]
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)
Otherwise, the good old Map will iterate over the values as if the structure were a list:
a // Map[("newVal" <> ToString@#) &]
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)
You should also look up KeyValueMap to see if that would make your task easier.
Edit
Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.
answered Dec 5 at 19:25
Shredderroy
1,4931115
add a comment |
If you would like to map over the keys to transform them into something else, you can use KeyMap:
a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
a // KeyMap[("newKey" <> #) &]
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)
Otherwise, the good old Map will iterate over the values as if the structure were a list:
a // Map[("newVal" <> ToString@#) &]
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)
You should also look up KeyValueMap to see if that would make your task easier.
Edit
Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.
answered Dec 5 at 19:25
Shredderroy
1,4931115
add a comment |
If you would like to map over the keys to transform them into something else, you can use KeyMap:
a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
a // KeyMap[("newKey" <> #) &]
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)
Otherwise, the good old Map will iterate over the values as if the structure were a list:
a // Map[("newVal" <> ToString@#) &]
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)
You should also look up KeyValueMap to see if that would make your task easier.
Edit
Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.
answered Dec 5 at 19:25
Shredderroy
1,4931115
If you would like to map over the keys to transform them into something else, you can use KeyMap:
a = <|"0" -> 0, "1" -> 1, "2" -> 2|>;
a // KeyMap[("newKey" <> #) &]
(* <|"newKey0" -> 0, "newKey1" -> 1, "newKey2" -> 2|> *)
Otherwise, the good old Map will iterate over the values as if the structure were a list:
a // Map[("newVal" <> ToString@#) &]
(* <|"0" -> "newVal0", "1" -> "newVal1", "2" -> "newVal2"|> *)
You should also look up KeyValueMap to see if that would make your task easier.
Edit
Henrik Schumacher's succinct comment contains everything I have elaborated here. His comment had not been posted when I began writing this answer.
answered Dec 5 at 19:25
Shredderroy
1,4931115
answered Dec 5 at 19:25
Shredderroy
1,4931115
answered Dec 5 at 19:25
Shredderroy
1,4931115
answered Dec 5 at 19:25
Shredderroy
1,4931115
1,4931115
add a comment |
add a comment |
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1
Simply use
Map,KeyValueMaporKeyMap?– Henrik Schumacher
Dec 5 at 19:20
Can you tell what exactly do you want to do?
– Kuba♦
Dec 5 at 21:42
Woooops! Done! :)
– SLesslyTall
Dec 6 at 7:40
@SLesslyTall You see, you want
KeyValueMap[List] @ assobut who could've known :)– Kuba♦
Dec 6 at 7:53