Re: destructuring let and for
Thanks for the answer, I'll try to do as you suggest. Thanks On Tuesday, June 10, 2014 11:51:59 PM UTC+2, Paul G wrote: Hi Francesco, I apologize for using for earlier, as I did not explain how you should be using it. The comment of do something with rel should have indicated that it resolved to an expression, and those expressions would be returned in a seq (the for expression resolves to have a value of a seq). Given your last example, I could read it a couple of ways. My first interpretation is that you just need a way to convert names to nodes, and then to connect all the nodes. My preference would be to separate these steps, so the conversion would be done with: (map convert-to-node list-of-names) The result of this is then looped through to create the relations (as in my previous example, the relations are both ways, and not reflexive): (let [nodes (map convert-to-node list-of-names)] (for [node1 nodes, node2 nodes :when (not= node1 node2)] (nrl/create conn page1 page2 :links))) This creates a seq of all the relations, in both directions. So one relationship will be [Jupiter-Pluto] and another will be [Pluto-Jupiter]. To create one-way relationships, I suggest the use of indexes, as in my previous post. However, when I followed your link to the example data, I see that there are connections between some nodes and not others. In that case it would be preferable to create a mapping of names to nodes, and then as the relationships are required those nodes can be found easily: (def create-nodemap [names] (zipmap names (map convert-to-node names))) Now you can grab the nodes as needed to work with them: (defn connect [nodemap name1 name2] (nrl/create conn (nodemap name1) (nodemap name2 :link))) (let [nodemap (create-nodemap [jupiter hercules neptune pluto])] (connect nodemap jupiter hercules :link) (connect nodemap jupiter neptune :link) (connect nodemap jupiter pluto :link) (connect nodemap neptune pluto :link)) I am avoiding many tricks here that I'd use in reality, to avoid making it too obscure. Note that the above has links between Juptier, Neptune and Pluto, but Hercules is only linked to Jupiter. So we don't have everything connected to everything else. However, this approach is only useful in simple examples like this, since any real data set would be too large to write code for every connection. Instead, the actual data (coming from a csv file, or something) would be read and used to create the connections. What does your original data look like? Are you just trying to re-create the graph you linked to, or is the data available in some structured format? Paul On Tue, Jun 10, 2014 at 4:08 PM, Francesco Lunelli francesc...@gmail.com javascript: wrote: Thanks for the answer. If I understand well your code it's a partial answer to my question because if I'm not wrong it creates a link between to elements at a time. What I need is to create all the elements then create on them every kind of relation. I take as example a graph db used in another engine https://raw.githubusercontent.com/wiki/thinkaurelius/titan/images/graph-of-the-gods-2.png Here you have a graph of Roman gods, with the name of the gods and the links among them. So if I have for example a list of the names of Roman gods I need to create all the nodes, then connect them in various mode. I want to take the list '(jupiter saturn hercules neptune pluto ...) and cycling on it I want to creare the nodes. When I finished to create them I need to be able to call every node to crete the various links among them. For example I need to link jupiter with pluto, jupiter with neptun, neptun with pluto and so on. Thanks Francesco On Tuesday, June 10, 2014 7:43:21 PM UTC+2, Paul G wrote: Hi Francesco, You want to decouple your code from the data that it is operating on, so your code can operate regardless of the contents of the list. Otherwise, you'll need code that matches the list, in which case it could all be code anyway. Operating on arbitrary lists makes it easy to test simple examples too. A simple way to create links between pages might be like this (assuming that conn is in scope and initialized): (for [list-elt1 the-list, list-elt2 the-list :when (not= list-elt1 list-elt2)] (let [page1 (page-fn list-elt1) page2 (page-fn list-elt2) rel (nrl/create conn page1 page2 :links)] ;; do something with rel )) This creates links both ways. If you only want one-way links then the first approach that comes to mind (there are others, and they're probably better) is to index through the seq: (for [n (range (count the-list)), m (range (inc n) (count the-list))] (let [page1 (page-fn (nth the-list n)) page2 (page-fn (nth the-list m)) rel (nrl/create conn page1 page2 :links)] ;; do something with rel )) The general idea here is to use an
destructuring let and for
Hello everybody, I have a newbie question about destructuring and assigning and didn't find an answer in documentation or books. I have a list that contains an arbitrary number of elements for example '(one two three ...) I now only that elements are strings. I need to to take every element and use it as the name of a variable inside a let and assign the result of a funcion on that element to that variable. Somthing like this for example: (let [one (clojure.string/capitalize one) two (clojure.string/capitalize two) three (clojure.string/capitalize three)] ;; here I have access to vars one two three etc. ) where the names of the vars are taken from the list and values are obtained applying a function on the corresponding element of the list (the capitalize function il only an example, it could be everything else). If I do in this way (for [word [the quick brown fox]] (let [word (clojure.string/capitalize word)] (prn word))) it works, but I need to access the variables outside of the cycle for, after having defined and assigned everyone because I need to put in relation some of them. Thanks to everybody Francesco -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: destructuring let and for
Could you explain a little more what your end goal is? It sounds like you want a map, but without knowing more about the purpose, it's difficult to say. - James On 10 June 2014 16:43, Francesco Lunelli francesco.lune...@gmail.com wrote: Hello everybody, I have a newbie question about destructuring and assigning and didn't find an answer in documentation or books. I have a list that contains an arbitrary number of elements for example '(one two three ...) I now only that elements are strings. I need to to take every element and use it as the name of a variable inside a let and assign the result of a funcion on that element to that variable. Somthing like this for example: (let [one (clojure.string/capitalize one) two (clojure.string/capitalize two) three (clojure.string/capitalize three)] ;; here I have access to vars one two three etc. ) where the names of the vars are taken from the list and values are obtained applying a function on the corresponding element of the list (the capitalize function il only an example, it could be everything else). If I do in this way (for [word [the quick brown fox]] (let [word (clojure.string/capitalize word)] (prn word))) it works, but I need to access the variables outside of the cycle for, after having defined and assigned everyone because I need to put in relation some of them. Thanks to everybody Francesco -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: destructuring let and for
Thanks for the answer, I try to explain better what I have to do.
I need to create some nodes in Neo4j then I need to create relationships
between those nodes.
This is an example taken from necons doc.
(let [conn (nr/connect http://localhost:7474/db/data/;)
page1 (nn/create conn {:url http://clojurewerkz.org})
page2 (nn/create conn {:url http://clojureneo4j.info})
;; a relationship that indicates that page1 links to page2
rel (nrl/create conn page1 page2 :links)]
(println rel)))
They create two nodes called page1 and pag2 then connect them.
In my case I have a list of names, I want to create one node for each of
them with the possibility to work on nodes after they are created.
So if I have for example a list like this one (def mylist '(jjohn paul
mary)) I want to create three nodes calling them john paul and mary
storing the value John Paul Mary and after having created them I want
to be albe to connect nodes creating a relationship among them, with a
funciont like rel (nrl/create conn john paul :friend)]
I hope this example explain better my needs.
Thanks in advance
Francesco
On Tuesday, June 10, 2014 6:11:16 PM UTC+2, James Reeves wrote:
Could you explain a little more what your end goal is?
It sounds like you want a map, but without knowing more about the purpose,
it's difficult to say.
- James
On 10 June 2014 16:43, Francesco Lunelli francesc...@gmail.com
javascript: wrote:
Hello everybody, I have a newbie question about destructuring and
assigning and didn't find an answer in documentation or books.
I have a list that contains an arbitrary number of elements for example
'(one two three ...) I now only that elements are strings.
I need to to take every element and use it as the name of a variable
inside a let and assign the result of a funcion on that element to that
variable.
Somthing like this for example:
(let [one (clojure.string/capitalize one)
two (clojure.string/capitalize two)
three (clojure.string/capitalize three)]
;; here I have access to vars one two three etc.
)
where the names of the vars are taken from the list and values are
obtained applying a function on the corresponding element of the list (the
capitalize function il only an example, it could be everything else).
If I do in this way
(for [word [the quick brown fox]] (let [word
(clojure.string/capitalize word)] (prn word)))
it works, but I need to access the variables outside of the cycle for,
after having defined and assigned everyone because I need to put in
relation some of them.
Thanks to everybody
Francesco
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javascript:
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Re: destructuring let and for
Hi Francesco,
You want to decouple your code from the data that it is operating on, so
your code can operate regardless of the contents of the list. Otherwise,
you'll need code that matches the list, in which case it could all be code
anyway. Operating on arbitrary lists makes it easy to test simple examples
too.
A simple way to create links between pages might be like this (assuming
that conn is in scope and initialized):
(for [list-elt1 the-list, list-elt2 the-list :when (not= list-elt1
list-elt2)]
(let [page1 (page-fn list-elt1)
page2 (page-fn list-elt2)
rel (nrl/create conn page1 page2 :links)]
;; do something with rel
))
This creates links both ways.
If you only want one-way links then the first approach that comes to mind
(there are others, and they're probably better) is to index through the seq:
(for [n (range (count the-list)), m (range (inc n) (count the-list))]
(let [page1 (page-fn (nth the-list n))
page2 (page-fn (nth the-list m))
rel (nrl/create conn page1 page2 :links)]
;; do something with rel
))
The general idea here is to use an arbitrary var to represent your list
elements and pages.
Does this address your issue?
Regards,
Paul
On Tue, Jun 10, 2014 at 1:04 PM, Francesco Lunelli
francesco.lune...@gmail.com wrote:
Thanks for the answer, I try to explain better what I have to do.
I need to create some nodes in Neo4j then I need to create relationships
between those nodes.
This is an example taken from necons doc.
(let [conn (nr/connect http://localhost:7474/db/data/;)
page1 (nn/create conn {:url http://clojurewerkz.org})
page2 (nn/create conn {:url http://clojureneo4j.info})
;; a relationship that indicates that page1 links to page2
rel (nrl/create conn page1 page2 :links)]
(println rel)))
They create two nodes called page1 and pag2 then connect them.
In my case I have a list of names, I want to create one node for each of
them with the possibility to work on nodes after they are created.
So if I have for example a list like this one (def mylist '(jjohn
paul mary)) I want to create three nodes calling them john paul and
mary storing the value John Paul Mary and after having created them I
want to be albe to connect nodes creating a relationship among them, with a
funciont like rel (nrl/create conn john paul :friend)]
I hope this example explain better my needs.
Thanks in advance
Francesco
On Tuesday, June 10, 2014 6:11:16 PM UTC+2, James Reeves wrote:
Could you explain a little more what your end goal is?
It sounds like you want a map, but without knowing more about the
purpose, it's difficult to say.
- James
On 10 June 2014 16:43, Francesco Lunelli francesc...@gmail.com wrote:
Hello everybody, I have a newbie question about destructuring and
assigning and didn't find an answer in documentation or books.
I have a list that contains an arbitrary number of elements for example
'(one two three ...) I now only that elements are strings.
I need to to take every element and use it as the name of a variable
inside a let and assign the result of a funcion on that element to that
variable.
Somthing like this for example:
(let [one (clojure.string/capitalize one)
two (clojure.string/capitalize two)
three (clojure.string/capitalize three)]
;; here I have access to vars one two three etc.
)
where the names of the vars are taken from the list and values are
obtained applying a function on the corresponding element of the list (the
capitalize function il only an example, it could be everything else).
If I do in this way
(for [word [the quick brown fox]] (let [word
(clojure.string/capitalize word)] (prn word)))
it works, but I need to access the variables outside of the cycle for,
after having defined and assigned everyone because I need to put in
relation some of them.
Thanks to everybody
Francesco
--
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Groups Clojure group.
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your first post.
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Re: destructuring let and for
Thanks for the answer.
If I understand well your code it's a partial answer to my question because
if I'm not wrong it creates a link between to elements at a time. What I
need is to create all the elements then create on them every kind of
relation.
I take as example a graph db used in another
engine
https://raw.githubusercontent.com/wiki/thinkaurelius/titan/images/graph-of-the-gods-2.png
Here you have a graph of Roman gods, with the name of the gods and the
links among them. So if I have for example a list of the names of Roman
gods I need to create all the nodes, then connect them in various mode.
I want to take the list '(jupiter saturn hercules neptune pluto
...) and cycling on it I want to creare the nodes. When I finished to
create them I need to be able to call every node to crete the various links
among them. For example I need to link jupiter with pluto, jupiter with
neptun, neptun with pluto and so on.
Thanks
Francesco
On Tuesday, June 10, 2014 7:43:21 PM UTC+2, Paul G wrote:
Hi Francesco,
You want to decouple your code from the data that it is operating on, so
your code can operate regardless of the contents of the list. Otherwise,
you'll need code that matches the list, in which case it could all be code
anyway. Operating on arbitrary lists makes it easy to test simple examples
too.
A simple way to create links between pages might be like this (assuming
that conn is in scope and initialized):
(for [list-elt1 the-list, list-elt2 the-list :when (not= list-elt1
list-elt2)]
(let [page1 (page-fn list-elt1)
page2 (page-fn list-elt2)
rel (nrl/create conn page1 page2 :links)]
;; do something with rel
))
This creates links both ways.
If you only want one-way links then the first approach that comes to mind
(there are others, and they're probably better) is to index through the seq:
(for [n (range (count the-list)), m (range (inc n) (count the-list))]
(let [page1 (page-fn (nth the-list n))
page2 (page-fn (nth the-list m))
rel (nrl/create conn page1 page2 :links)]
;; do something with rel
))
The general idea here is to use an arbitrary var to represent your list
elements and pages.
Does this address your issue?
Regards,
Paul
On Tue, Jun 10, 2014 at 1:04 PM, Francesco Lunelli francesc...@gmail.com
javascript: wrote:
Thanks for the answer, I try to explain better what I have to do.
I need to create some nodes in Neo4j then I need to create relationships
between those nodes.
This is an example taken from necons doc.
(let [conn (nr/connect http://localhost:7474/db/data/;)
page1 (nn/create conn {:url http://clojurewerkz.org})
page2 (nn/create conn {:url http://clojureneo4j.info})
;; a relationship that indicates that page1 links to page2
rel (nrl/create conn page1 page2 :links)]
(println rel)))
They create two nodes called page1 and pag2 then connect them.
In my case I have a list of names, I want to create one node for each of
them with the possibility to work on nodes after they are created.
So if I have for example a list like this one (def mylist '(jjohn
paul mary)) I want to create three nodes calling them john paul and
mary storing the value John Paul Mary and after having created them I
want to be albe to connect nodes creating a relationship among them, with a
funciont like rel (nrl/create conn john paul :friend)]
I hope this example explain better my needs.
Thanks in advance
Francesco
On Tuesday, June 10, 2014 6:11:16 PM UTC+2, James Reeves wrote:
Could you explain a little more what your end goal is?
It sounds like you want a map, but without knowing more about the
purpose, it's difficult to say.
- James
On 10 June 2014 16:43, Francesco Lunelli francesc...@gmail.com wrote:
Hello everybody, I have a newbie question about destructuring and
assigning and didn't find an answer in documentation or books.
I have a list that contains an arbitrary number of elements for example
'(one two three ...) I now only that elements are strings.
I need to to take every element and use it as the name of a variable
inside a let and assign the result of a funcion on that element to that
variable.
Somthing like this for example:
(let [one (clojure.string/capitalize one)
two (clojure.string/capitalize two)
three (clojure.string/capitalize three)]
;; here I have access to vars one two three etc.
)
where the names of the vars are taken from the list and values are
obtained applying a function on the corresponding element of the list (the
capitalize function il only an example, it could be everything else).
If I do in this way
(for [word [the quick brown fox]] (let [word
(clojure.string/capitalize word)] (prn word)))
it works, but I need to access the variables outside of the cycle for,
after having defined and assigned everyone because I need to put in
Re: destructuring let and for
Hi Francesco, I apologize for using for earlier, as I did not explain how you should be using it. The comment of do something with rel should have indicated that it resolved to an expression, and those expressions would be returned in a seq (the for expression resolves to have a value of a seq). Given your last example, I could read it a couple of ways. My first interpretation is that you just need a way to convert names to nodes, and then to connect all the nodes. My preference would be to separate these steps, so the conversion would be done with: (map convert-to-node list-of-names) The result of this is then looped through to create the relations (as in my previous example, the relations are both ways, and not reflexive): (let [nodes (map convert-to-node list-of-names)] (for [node1 nodes, node2 nodes :when (not= node1 node2)] (nrl/create conn page1 page2 :links))) This creates a seq of all the relations, in both directions. So one relationship will be [Jupiter-Pluto] and another will be [Pluto-Jupiter]. To create one-way relationships, I suggest the use of indexes, as in my previous post. However, when I followed your link to the example data, I see that there are connections between some nodes and not others. In that case it would be preferable to create a mapping of names to nodes, and then as the relationships are required those nodes can be found easily: (def create-nodemap [names] (zipmap names (map convert-to-node names))) Now you can grab the nodes as needed to work with them: (defn connect [nodemap name1 name2] (nrl/create conn (nodemap name1) (nodemap name2 :link))) (let [nodemap (create-nodemap [jupiter hercules neptune pluto])] (connect nodemap jupiter hercules :link) (connect nodemap jupiter neptune :link) (connect nodemap jupiter pluto :link) (connect nodemap neptune pluto :link)) I am avoiding many tricks here that I'd use in reality, to avoid making it too obscure. Note that the above has links between Juptier, Neptune and Pluto, but Hercules is only linked to Jupiter. So we don't have everything connected to everything else. However, this approach is only useful in simple examples like this, since any real data set would be too large to write code for every connection. Instead, the actual data (coming from a csv file, or something) would be read and used to create the connections. What does your original data look like? Are you just trying to re-create the graph you linked to, or is the data available in some structured format? Paul On Tue, Jun 10, 2014 at 4:08 PM, Francesco Lunelli francesco.lune...@gmail.com wrote: Thanks for the answer. If I understand well your code it's a partial answer to my question because if I'm not wrong it creates a link between to elements at a time. What I need is to create all the elements then create on them every kind of relation. I take as example a graph db used in another engine https://raw.githubusercontent.com/wiki/thinkaurelius/titan/images/graph-of-the-gods-2.png Here you have a graph of Roman gods, with the name of the gods and the links among them. So if I have for example a list of the names of Roman gods I need to create all the nodes, then connect them in various mode. I want to take the list '(jupiter saturn hercules neptune pluto ...) and cycling on it I want to creare the nodes. When I finished to create them I need to be able to call every node to crete the various links among them. For example I need to link jupiter with pluto, jupiter with neptun, neptun with pluto and so on. Thanks Francesco On Tuesday, June 10, 2014 7:43:21 PM UTC+2, Paul G wrote: Hi Francesco, You want to decouple your code from the data that it is operating on, so your code can operate regardless of the contents of the list. Otherwise, you'll need code that matches the list, in which case it could all be code anyway. Operating on arbitrary lists makes it easy to test simple examples too. A simple way to create links between pages might be like this (assuming that conn is in scope and initialized): (for [list-elt1 the-list, list-elt2 the-list :when (not= list-elt1 list-elt2)] (let [page1 (page-fn list-elt1) page2 (page-fn list-elt2) rel (nrl/create conn page1 page2 :links)] ;; do something with rel )) This creates links both ways. If you only want one-way links then the first approach that comes to mind (there are others, and they're probably better) is to index through the seq: (for [n (range (count the-list)), m (range (inc n) (count the-list))] (let [page1 (page-fn (nth the-list n)) page2 (page-fn (nth the-list m)) rel (nrl/create conn page1 page2 :links)] ;; do something with rel )) The general idea here is to use an arbitrary var to represent your list elements and pages. Does this address your issue? Regards, Paul On Tue, Jun 10, 2014 at 1:04 PM, Francesco Lunelli francesc...@gmail.com wrote: Thanks for the
