see also this page:
http://clojure.org/sequences
where for is listed among the seq library functions
HTH
Gianluca
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(for [[x y z] {:a "aa" :b "bb" :c "cc"}] [x y z])
([:c "cc" nil] [:b "bb" nil] [:a "aa" nil]);; WTF?
So her, I guess, your taking each entry in the map and destructuring them into
the three vars x, y, and z. Since each map entry is a pair, the third var z
will be nil.
Erik.
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i farta
x and y are destructured into the key and value of each map entry. Z is
nil.
The second example uses seq to convert the map into a sequence of map
entries and then it destructures the seq (not the map entries themselves).
The third example does destructure the map entries.
(let [[a b c] [1 2]] [a
On 06/06/2015 05:01, Sean Corfield wrote:
Page 84 is where it shows that maps are a sequence of pairs.
The destructuring in James's code is on vectors -- the pairs in the
sequence.
Hope that helps?
Sean
Page 84 describes the sequence abstraction in general but it's the
implicit seq in for
Page 84 is where it shows that maps are a sequence of pairs.
The destructuring in James's code is on vectors -- the pairs in the
sequence.
Hope that helps?
Sean
On Fri, Jun 5, 2015 at 8:11 PM, gvim wrote:
> Yes, I'm fine with the concept. Just can't remember coming across it in
> the textbook
Yes, I'm fine with the concept. Just can't remember coming across it in
the textbooks but maybe I wasn't paying attention :)
gvim
On 06/06/2015 04:08, Sean Corfield wrote:
It’s because if you treat a hash map as a sequence — as `for` does — you get a
sequence of pairs (key/value — map entrie
It’s because if you treat a hash map as a sequence — as `for` does — you get a
sequence of pairs (key/value — map entries):
(seq {:a 1 :b 2})
;;=> ([:a 1] [:b 2])
Does that help?
Sean
> On Jun 5, 2015, at 7:41 PM, gvim wrote:
>
> I must re-read "Clojure Programming" (O'Reilly
I must re-read "Clojure Programming" (O'Reilly) in that case as I don't
recall the authors mentioning this kind of destructuring.
gvim
On 06/06/2015 03:33, Fluid Dynamics wrote:
On Friday, June 5, 2015 at 10:07:05 PM UTC-4, g vim wrote:
That works but I missed this possibility because I'
On Friday, June 5, 2015 at 10:07:05 PM UTC-4, g vim wrote:
>
> That works but I missed this possibility because I'm still not clear how:
>
> (group-by :email signs)
>
> which produces a map of the form:
>
> {"a...@gmail.com "
> [{:email "a...@gmail.com ", :sign "Cancer", :planet
> "M
That works but I missed this possibility because I'm still not clear how:
(group-by :email signs)
which produces a map of the form:
{"a...@gmail.com"
[{:email "a...@gmail.com", :sign "Cancer", :planet "Mars", :surname
"Blogs", :first_name "Joe"}
. ]}
can be destructured
Perhaps something like:
(defn planet-sign-map [signs]
(into {} (map (juxt :planet :sign) signs)))
(defn extract-planet-signs [signs]
(for [[email signs] (group-by :email signs)]
{:email email, :signs (planet-sign-map signs)}))
(defn find-planet-signs [emails]
(extract-planet-signs (get
I have a YeSQL query:
(get-signs {:em emails}) ;; emails is a vector of email address strings
... which produces this list of maps:
(
{:email "a...@gmail.com", :sign "Scorpio", :planet "Mercury", :surname
"Blogs", :first_name "Joe"}
{:email "a...@gmail.com", :sign "Leo", :planet "Moon", :surn
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