Hi Ganesh,
Please don’t do it this way, as you’re opening yourself to sql-injection. When
doing parameterized queries in sql, please reach for prepared statements.
As others have mentioned, next.jdbc with a sprinkle of honeysql on top should
be exact what you’re looking for.
Erik.
--
i fa
Hey Ganesh,
Just to add to the above information, you may want to check out next.jdbc
as well. If you specifically want to create functions that return complete
SQL, then maybe this isn't what you want, but I just wanted to point out
parameterization in next.jdbc since you mentioned you're new to
The most straight forward approach is to simply define a different function
for each use case you have using the same approach.
At some point you will have to decide which function to call with what
input.
In more general terms, you want to think about taking an input (a map),
applying some trans
Hello Alpaware,
Thanks for the reply,
In the above, I just gave an example,
Bt this will be dynamic, Any number of keys can come, How to segregate and
assigned to
particular variable?
Thanking you.
--
With regards.
Ganesh N Neel
Welcome to Clojure!
You could just define a function taking a map as an argument and return the
query as a string using destructering [0]
(defn people [{:keys [table person id]}]
(str "SELECT * FROM " table " WHERE person_id = " person " ORDER BY " id))
You may want to have a look at Sean Corn
Hello Team,
I am new to clojure and I wanted to write a function where input from map
keys are passed as parameter as input to the sql query.
(def query-body1 "
select first_name, last_name
from ${table_name}
where
person_id=${person_id}
order by ${id}
")
(def query-body2 "
select first_nam
The reduce in your mapped function is already implemented by get-in. Other
possible implementations using get-in:
(defn map-in [coll ks f & args]
(->> coll
(map #(get-in % ks))
(map #(apply f % args
Or:
(defn map-in [coll ks f & args]
(map #(apply f (get
Is there anything for map which operates like update-in and assoc-in, where
we can call a function with the value looked up in a nested structure?
What I've come up with:
(defn map-in
"Returns a lazy sequence consisting of the results of
calling map on coll, for each value i
Thanks, that's very helpful!
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Please try these exercises if you want to know what a channel is:
https://github.com/halgari/clojure-conj-2013-core.async-examples/blob/master/src/clojure_conj_talk/core.clj
Op vrijdag 13 december 2013 11:01:57 UTC+1 schreef Joachim De Beule:
>
> Thanks, that indeed did the trick.
>
> More genera
Thanks, that indeed did the trick.
More generally it's not clear to me what makes a channel an "output
channel" or an "input channel". Aren't all channels input and output
channels depending on whether you read from or write to it?
Op vrijdag 13 december 2013 04:28:53 UTC+1 schreef Carlo:
>
On Thu, Dec 12, 2013 at 06:08:11PM -0800, Joachim De Beule wrote:
> I expected to see a sequence of the form "<><><>...". However, only one or
> very few ">" get printed, so I get a sequence "<>>>...". Why?
They're getting buffered. Try this:
(as/pipe (as/map< (fn [x] (print "<") (flush) x) sou
Dear list,
I'm playing around with core.async and I don't understand the following.
1) I make a "source" channel that emits a random number every second.
(def continue (atom true))
(def source (let [out (as/chan)]
(as/go-loop []
(when @continue
(as/pu
On 28 October 2013 05:23, Jiaqi Liu wrote:
>> 2013/10/28 Jiaqi Liu
>>>
>>> i really don't get it.
>>> Any suggestion??
>>
>>
>> Clojure data structures are immutable. clojure.core/assoc
>> produces a new data structure instead of changing the one you have.
>>
>> You can use an atom if you need t
Thanks for your suggests~
The above piece of code is just for test.
The practical problem i want to solve is that
-->read a very big log file (each line is like that : "user id, latitude,
longitude, timeStamp")
-->statistic the number of each user (store in a map like that { id1 100 ,
id2 200, id3
2013/10/28 Jiaqi Liu
> i really don't get it.
> Any suggestion??
>
Clojure data structures are immutable. clojure.core/assoc
produces a new data structure instead of changing the one you have.
You can use an atom if you need to update a map from doseq
but more likely you want to use the actual
Hi , all
I am new to Clojure.
For now , i have a piece of code :
(let [res {}]
(doseq [id [111 222 333]
num [2 3 4]]
(assoc res id num))
(count res))
i want to get the res {111 2 , 222 3 , 333 4} and count 3
but the repl return me {} and 0
i r
Hello,
A note about the code organization : I think you should strive to
separate the code that does side effects from the code that works on
the datastructures.
This means you could refactor your refactored version as such:
=> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
Here's the refactored version.user> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}]))
#'user/example
user>
(defn
Hi,
Am Mittwoch, 12. Juni 2013 06:39:59 UTC+2 schrieb Kelker Ryan:
>
> user> (defn update-counter [id xs]
>
> (let [at-after (drop-while #(not= id (:id %)) @xs)
> to-modify (-> at-after first :email)
> mod-key (-> to-modify keys first)
> location (
I've seen some interesting responses, but here's my solution. user> (def example
(ref
[{:id 1 :email {"a...@mail.com" 1}}
{:id 2 :email {"d...@mail.com" 1}}
{:id 3 :email {"g...@mail.com" 2}}
{:id 4 :email {"f...@mail.com" 2}}]))
#'user/example
user>
Solutions seem to depend on whether you have two or more mail addresses in
a ':emails' section or not.
If you have, you should identify the mail address of which you want to
increment the value.
Anyway, try below:
(dosync
(alter result
(fn [v]
(mapv second
(update-in (into {}
You *can* update this inside the vector, but if you want to key by :id, I
would personally recommend, you put the email data into a map and look it
up by :id, like this:
{1 {:id 1 :email {"a...@mail.com 1}}
2 {:id 2 :email {"d...@mail.com 1}}
3 {:id 3 :email {"g...@mail.com 2}}}
Best,
Alex
O
Thanks Meikel for the prompt reply, that does it.
Please can you elaborate on how I can use the solution below to update a
particular entry in the vector.
[{:id 1 :email {"a...@mail.com 1}}
{:id 2 :email {"d...@mail.com 1}}
{:id 3 :email {"g...@mail.com 2}}]
So I will like to write a functi
Hi,
Am Montag, 3. Juni 2013 22:16:54 UTC+2 schrieb Yinka Erinle:
>
> Given I have the following
> (def result (ref [ { :id 1 :emails { "yi...@mail.com " 1}} ]
> ) )
>
> I like to alter the result in a transaction to become
> [{:id 1 :emails { "yi...@mail.com " 2}}]; increment the
> counter
Hi,
I struggling to find a way to alter a value in a map that resides in a
vector.
Given I have the following
(def result (ref [ { :id 1 :emails { "yi...@mail.com" 1}} ] ) )
I like to alter the result in a transaction to become
[{:id 1 :emails { "yi...@mail.com" 2}}]; increment the counter
HI, I'm looking for functionality like the "featurec" function, but I need
to be able to capture the unused keys.
Here is how "featurec" currently works:
(run* [q]
(== q {:a 1 :b 2})
(featurec q {:b 2})))
==> ({:a 1 :b 2})
However, I need to capture the keys th
Look at clojure.walk for mapping functions over nested structures:
(defn mapv-in [f coll]
(clojure.walk/prewalk #(if (coll? %) % (f %)) coll))
Clojure walk api: http://clojure.github.com/clojure/clojure.walk-api.html
On Friday, October 5, 2012 7:58:30 AM UTC+2, nchurch wrote:
>
> I ended u
I ended up needing the following utility, modified from the Clojure
source:
(defn mapv-in
"maps f over a nested vector structure"
([f coll]
(let [f #(if (coll? %)(mapv-in f %)(f %))]
(-> (reduce (fn [v o] (conj! v (f o))) (transient []) coll)
persistent!
I wrote just as
Confirmed -- thanks for the report.
Stu
> Hi,
>
> It seems reduce-kv doesn't reduce a sorted-map in the correct order.
>
> Example -
>
> user> (def *sm (into (sorted-map) {:aa 1 :zz 2 :bb 3 :yy 4 :cc 5 :xx 6}))
> ;=> #'user/*sm
>
> user> *s
Sounds like a bug to me, in that it doesn't behave as I would expect.
On Thu, Aug 9, 2012 at 7:29 PM, Baishampayan Ghose wrote:
> Hi,
>
> It seems reduce-kv doesn't reduce a sorted-map in the correct order.
>
> Example -
>
> user> (def *sm (into (sorted-map) {:
Hi,
It seems reduce-kv doesn't reduce a sorted-map in the correct order.
Example -
user> (def *sm (into (sorted-map) {:aa 1 :zz 2 :bb 3 :yy 4 :cc 5 :xx 6}))
;=> #'user/*sm
user> *sm
;=> {:aa 1, :bb 3, :cc 5, :xx 6, :yy 4, :zz 2}
;; plain reduce
user> (reduce (fn [re
Hi,
(defn example
[& args]
(let [[opts args] (let [opts? (first args)]
(if (map? opts?)
[opts? (next args)]
[nil args]))]
(reduce str args)))
Kind regards
Meikel
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You received this message because you are subscribed
> My question is: I would like to allow the first parameter to be an
> (optional) map containing key values for the function. What's a clean,
> readable way to do that?
How about this:
(defn example [& args]
(let [opts (when map? (first args))
args (when opts (next args))]
(redu
I've just started playing with Clojure and I have a newbie question:
I have an anonymous function that takes a variable number of parameters. I
coded it so it takes a list of strings or functions that return strings and
concatenates the resultant strings like so:
(defn example [& args] (reduce
Alan Malloy writes:
Hi Alan,
> If I were using this for some performance-critical task and never
> disjoined, I'd use ninjudd's version. Otherwise I'd use mine, just
> because it's easier to build and tweak since it's in clojure.
I tried your implementation, and I couldn't see any relevant slow
Well, I wrote the clojure version after boasting to ninjudd that
deftype would let you do it without writing any java at all. I did
some simple-minded benchmarking, and while I don't recall the exact
numbers his java version is ~10-50% faster. If you look through the
git logs, somewhere I have a ve
Alan Malloy writes:
Hi Alan,
> ArrayMap isn't very performant for large collections. You might like
> https://github.com/flatland/ordered
in my clojure app, I totally rely on ordered sets. Currently, I use
https://github.com/ninjudd/ordered-set
for which I've implemented transient support
Note that it's still pretty immature - I started writing it last
weekend. It's tested fairly thoroughly, and I spent four or five days
hunting down the best performance I could, so it should be perfectly
usable. However, if you have any problems please let me know.
Especially, if you plan to disso
array-map turns into a hashmap after ten insertions, currently, but
that's far from guaranteed:
user> (->> {}
(iterate #(assoc % (rand-int 1e6) 1))
(drop-while (comp #{(class {})} class))
(first)
(count))
10
My ordered-set/map are now available on cloja
I wonder at what point array-map becomes a hash-map? Maybe I could use it?
On second thought, I don't really want to depend on something so
flimsy.
Alan, is your ordered map code available on clojars?
Alex
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Groups "Cloj
ries from the map.
>
> Note that a map of refs doesn't cut it as a substitute for a
> ConcurrentHashMap if keys will be added/removed by multiple threads,
> and sticking the entire map in an atom doesn't if you want to support
> more concurrency than a plain old Collection
t though by putting a
WeakReference(val) in in a wrapper layer and using a ReferenceQueue
and a thread that drains the queue every so often to prune dead
Map.Entries from the map.
Note that a map of refs doesn't cut it as a substitute for a
ConcurrentHashMap if keys will be added/removed by mul
Beware the devil hidden in the details:
"
Note that an array map will only maintain sort order when
un-'modified'. Subsequent assoc-ing will eventually cause it to
'become' a hash-map.
"
2011/6/25 Alex Baranosky :
> Ha! Perfect. Thanks.
>
> On Sat, Jun 25, 2011 at 4:00 PM, James Estes wrote:
>>
ArrayMap isn't very performant for large collections. You might like
https://github.com/flatland/ordered
On Jun 25, 1:11 pm, Alex Baranosky
wrote:
> Ha! Perfect. Thanks.
>
>
>
>
>
>
>
> On Sat, Jun 25, 2011 at 4:00 PM, James Estes wrote:
> > ArrayMap?
> >http://clojure.org/data_structures#toc2
Ha! Perfect. Thanks.
On Sat, Jun 25, 2011 at 4:00 PM, James Estes wrote:
> ArrayMap?
> http://clojure.org/data_structures#toc21
>
> James
>
>
> On Sat, Jun 25, 2011 at 1:55 PM, Alex Baranosky
> wrote:
> > What are some options for having a map that guarantees ordering of its
> keys
> > in Clo
ArrayMap?
http://clojure.org/data_structures#toc21
James
On Sat, Jun 25, 2011 at 1:55 PM, Alex Baranosky
wrote:
> What are some options for having a map that guarantees ordering of its keys
> in Clojure? (note: sorted-map won't do!) My first try was to use
> LinkedHashMap, but am running into
What are some options for having a map that guarantees ordering of its keys
in Clojure? (note: sorted-map won't do!) My first try was to use
LinkedHashMap, but am running into exceptions of the
" java.util.LinkedHashMap cannot be cast to clojure.lang.Associative"
variety.
So then I tried to use e
You're right, the scenario that I described doesn't need it. In my
actual code I need it because the function actually reads
#(conj (or % #{}) constraint#)
If I don't do that, I get a list instead of a set.
On Jul 5, 5:12 pm, Meikel Brandmeyer wrote:
> Hi,
>
> Am 05.07.2009 um 07:27 schrieb Row
Hi,
Am 05.07.2009 um 07:27 schrieb Rowdy Rednose:
user=> (dosync (alter gnu-rms update-in [:key1 :key2 :key3] #(conj %
"foo")))
{:key1 {:key2 {:key3 #{"foo"
You actually don't need the anonymous function...
(dosync
(alter gnu-rms update-in [:key1 :key2 :key3] conj "foo"))
Sincerely
M
On Jul 5, 1:20 pm, Adrian Cuthbertson
wrote:
> (dosync (alter rms assoc-in [:key1 :key2 :key3] "foo"))
> {:key1 {:key2 {:key3 "foo"}}}
I just found update-in, which is even better, as I want to update a
set:
user=> (def gnu-rms (ref {:key1 {:key2 {:key3 #{))
#'user/gnu-rms
user=> (dosync
On Jul 5, 1:23 pm, Richard Newman wrote:
> However, I'd point out that:
>
> * This might be a sign that you're doing things 'wrong'.
Could be. I'm still figuring out how to do things the functional way.
The reason I have these nested maps is to give my data structure. I
don't want to have a loos
Much better! Thanks.
On Jul 5, 1:20 pm, Adrian Cuthbertson
wrote:
> You could use assoc-in...
>
> (def rms (ref {:key1 {:key2 {:key3 #{))
>
> (dosync (alter rms assoc-in [:key1 :key2 :key3] "foo"))
> {:key1 {:key2 {:key3 "foo"}}}
>
> Rgds, Adrian.
>
> On Sun, Jul 5, 2009 at 6:07 AM, Rowdy Re
Rowdy,
> Do I really have to assoc all the way through to the inner map? Isn't
> there a more succinct way to write this? In Common Lisp there's (setf
> (getf ...))
Remember, Clojure's data structures are immutable. You're not adding a
value to a set -- what you're describing is (in Clojure) a
You could use assoc-in...
(def rms (ref {:key1 {:key2 {:key3 #{))
(dosync (alter rms assoc-in [:key1 :key2 :key3] "foo"))
{:key1 {:key2 {:key3 "foo"}}}
Rgds, Adrian.
On Sun, Jul 5, 2009 at 6:07 AM, Rowdy Rednose wrote:
>
> Say I have a data structure like this
>
> (def ref-map-map-map-set
Say I have a data structure like this
(def ref-map-map-map-set (ref {:key1 {:key2 {:key3 #{))
If I want to add a new member to the set which is the value of :key3,
I currently do this:
(dosync
(let [key1 (:key1 @ref-map-map-map-set)
key2 (:key2 key1)
key3 (:key3 key2)]
(re
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