Clojure is a Lisp dialect for the Java Virtual Machine. Its main features include a software transactional memory system for coherent updates to data structures, transparent access to Java libraries, a dynamic REPL development environment, runtime polymorphism, and built-in concurrent programming ...
2
votes
2answers
44 views
clojure - finding first match in recursive search
I am searching a recursive solution space and would like to return the first match I find. (I am using this to solve sudoku, but I guess this would apply to any recursively defined problem or ...
2
votes
0answers
36 views
single-threaded socket server
I wrote a basic Clojure single-threaded socket server, mostly following Java examples; in particular I'd appreciate feedback on three things,
how I handle mutable state (I/O, managing connections).
...
3
votes
2answers
59 views
Mergesort implementation in Clojure
(defn merge [pred left right]
(loop [v [] l left r right] ; v is a vector, so conj will append to the end
(if (and (seq l) (seq r)) ; if both left and right are not empty
(if ...
3
votes
1answer
68 views
Is there a better way to extract a single value instead of a sequence?
The following code works, but I'd like to re-write, so that a single index is returned, rather than a sequence of indexes visited.
Here are the defs and function.
(def usage-vec-len 13)
(def ...
5
votes
1answer
87 views
Excessive use of let a problem in Clojure?
I have this set of functions - it works, but I'm concerned about the use of lets.
(defn- create-counts [coll]
"Computes how many times did each 'next state' come from a 'previous state'.
The ...
2
votes
0answers
69 views
Making my back-propagation clojure code more idiomatic
I've written an implementation of the back-propagation algorithm in clojure (here). This is my first attempt at clojure where the code totals more than ten lines and so it is not very idiomatic; ...
1
vote
2answers
77 views
Discovering words from letters in Clojure (Letterpress Solver)
I created a Letterpress solver that will take a string of letters and return a list of valid words that can be constructer with the provided letters. Not all letters need to be used in each word.
...
2
votes
1answer
102 views
Idiomatic Clojure? Performant & functional enough?
Problem
Disclaimer: This is my first clojure function & I'm still busy finishing the last chapters of "Programming Clojure". Thanks! :)
I am writing a function to randomly flood-fill parts of a ...
1
vote
1answer
63 views
How can I simplify the following to avoid sequence of maps?
Given the following code, I have written a for loop that returns a key and value (0 or 1) of file names passed. 1 means present, and 0 means not present.
Is there a way to construct a flat map ...
2
votes
0answers
109 views
Inverted index in Clojure - performance vs. idiomatic code
I have this code to create an inverted index from a directory of text files:
(def p (re-pattern #"[^\p{L}&&[^\p{M}]]"))
(defn invert[file]
(let [f (.getName file)
tokens (.split p ...
4
votes
0answers
104 views
Shepard Tone stream generation in Clojure
This is my work to generate an infinite Shepard Tone. It is written in Clojure and works by generating repeating streams of incrementing frequencies, converting those to values on a sine wave and then ...
0
votes
0answers
76 views
Shuffling algorithms by a Clojure Novice
The shuffle descriptions can be seen here... Shuffling
Am I using Clojure idioms and going with the grain of the language?
A few things that concern me..
Am I doing too much logic in my let ...
2
votes
1answer
68 views
Calculating pi in clojure - any suggestions
Clojure newbie here, trying to get my head around it. Obviously there are better ways of obtaining pi, but for educational purposes, how is the code below?
(defn leibniz-numerator [x] (* (- (rem x 4) ...
5
votes
1answer
108 views
First Go at Clojure and Functional Programming in General
Here's the code...
My goal is to simulate a Pile shuffle of a vector.
Here's the function..
(defn pile
([cards] (pile cards 3 1))
([cards num_piles] (pile cards num_piles 1))
([cards ...
1
vote
1answer
53 views
Clojure: Find specific element in HTML tree
I am trying to find all "link" elements that link to RSS feeds in a data structure created by clj-tagsoup. I wrote the following code, which seems to work fine. But: I come from a Java background and ...
0
votes
1answer
58 views
Idiomatic letterpress cheater
Hello dear Code Reviewers,
I'm playing around with Clojure and am having a lot of fun. It's quite hard to go from imperative languages to Clojure, and I need some guidance on how to make the ...
4
votes
1answer
88 views
String-splitting function
This function was hard to write as a Clojure newbie, and I don't like the result.
Can you help me find a better (more readable) way to do it?
(defn split-seq
"Splits a seq into blocks defined by ...
5
votes
4answers
258 views
How to write this small program better?
This is just a fun little exercise I had to do for a homework once (in Java rather than Clojure though). Basically, the goal is to find the number of different coin stacks you can build with the coins ...
4
votes
3answers
211 views
Critique my Clojure “Game of Life” code
I'm a Clojure n00b (but am experienced with other languages) and am learning the language as I find time - enjoying it so far, though the strange dreams and accidental use of parenthesis elsewhere ...
1
vote
1answer
72 views
Idiomatic text munging in Clojure
In getting accustomed to Clojure syntax, I wrote the following stutter function:
(defn doublelist [coll]
(flatten (map (fn [x] [x x]) coll)))
(defn stutter [s]
(clojure.string/join
" " ...
2
votes
1answer
116 views
Find largest two numbers from list using clojure
I'm trying to write a function that finds the largest two numbers from a list of positive integers in Clojure.
I've toyed around with Scheme in the past, but I'm very new to Clojure. This is what I ...
2
votes
2answers
86 views
More concise and/or idiomatic max subarray in Clojure?
I've implemented the following two versions of the classic "Max Sub-Array" problem in Clojure, using the Kadane algorithm.
First with loop / recur
(defn max-sub-array [A]
(loop [x (first A)
...
5
votes
1answer
190 views
Depth-first search algorithm in clojure
Context
As an exercise for myself (I'm learning clojure). I wanted to implement the Depth-first search algorithm.
How I did it
Using recursion
(def graph
{:s {:a 3 :d 4}
:a {:s 3 :d 5 :b 4}
...
3
votes
1answer
194 views
Connect Four: Bitboard checking algorithm
I'm rather new to Clojure and so I decided to program a Connect Four for fun and learning.
The code below is a Clojure implementation of this bitboard algorithm.
The whole code can be found here: ...
0
votes
1answer
94 views
Calculating a factorial with parallel sub-computations using pmap, pvalues and pcalls
In an attempt to learn more about Clojure's parallel computation functions, I devised the following task: calculate a factorial in parallel using pmap, pcalls and pvalues.
The idea is to split the ...
3
votes
0answers
75 views
Toggle chart series in clojurescript
I'm toggling on/off series in chart and was wondering if I was doing anything crazy.
Is the atom really a good idea here?
;; ================ Graph data ================
(def serie1 {:label "Bar" ...
3
votes
1answer
138 views
Implementation of Python's re.split in Clojure (with capturing parentheses)
If you use capturing parenthesis in the regular expression pattern in Python's re.split() function, it will include the matching groups in the result (Python's documentation).
I need this in my ...
6
votes
2answers
193 views
Expanding a map, style guidance
I have a map that I want to 'expand' into an infinite sequence in the following manner:
{0 'zero 3 'three 10 'ten}
=>
('zero 'zero 'zero 'three 'three 'three 'three 'three 'three 'three 'ten 'ten ...
4
votes
2answers
538 views
higher order fizzbuzz! clojure
make it better! requirement: support arbitrary number of factors, not just 3 & 5.
(ns fizzbuzz.core
(:use [clojure.contrib.string :only (join)]))
(def targets (sorted-map 3 "fizz" 5 "buzz" 7 ...
4
votes
3answers
641 views
Find the common characters between two strings without using set operations
Below are two implementations of the problem "find the characters in common between two strings" - in Clojure without using collections / set operations.
Are these approaches sufficiently idiomatic ...
7
votes
2answers
253 views
Powerset in Clojure
I think I have correctly implemented Powerset in Clojure.
(use '(clojure set))
(defn powerset [input result]
(if (nil? (first input))
(concat result #{})
(set (reduce concat
...
6
votes
1answer
342 views
Clojure TicTacToe (Logic, no Gui)
I whipped this up last night and was wondering if anyone had any thoughts/comments on it; for example, on:
Code organisation
Coding style
Other improvements
Semantic errors
All feedback is ...
7
votes
1answer
146 views
Tips on good clojure style
I've implementing this algorithm in Java, Scala, and Clojure to show my team-mates. I know the code works as expected. What I'm looking for is tips on good clojure style.
(ns gaming.online.ranking
...
2
votes
1answer
196 views
idiomatic clojure (map from sequence generation)
It's my first clojure script (simple word translator based on wikipedia), and I guess there are things which could be simplified / done more idiomatic way. Specifically, I wonder if get-translations ...
3
votes
2answers
288 views
Clojure MapReduce Reducer
This program forms the reducer of a Hadoop MapReduce job. It reads data in from stdin that is tab delimited.
foo 1
foo 1
bar 1
and outputs
foo 2
bar 1
Any suggestions for ...
5
votes
1answer
241 views
Enumerate k-combinations in Clojure (P26 from 99 problems)
I've been playing with Clojure for the last few evenings, going through the well known 99 problems (I'm using a set adapted for Scala).
Problem 26 calls for a function that, given a set S and a no. ...
7
votes
2answers
716 views
Review my implementation of Viterbi in Clojure?
I would be grateful for suggestions that I use to turn this code into more idiomatic clojure code.
I've probably done some pretty horrendous things here, but I'm throwing it out for people to give me ...
7
votes
1answer
354 views
Unix sort in Clojure
I am implementing Unix sort in Clojure. This is my first program, and I would like some feedback regarding any non-idiomatic, harmful code and any other best practices I can include in future ...
2
votes
1answer
148 views
More concise way to write this clojure code adapted from map-invert?
I wanted to do the following:
Count the frequencies of words in a text (over 5 letters)
Invert the map of words to frequencies, but group together words that have the same frequency in the ...
4
votes
1answer
120 views
Improve this Clojure code to construct a tail cmd?
I wrote this without much thought:
(defn- tail-cmd
"Construct a tail cmd"
[file n & ignore-patterns]
(clojure.string/join
" | "
(flatten [(format "tail -n %s -f %s" (or n 200) file)
...
1
vote
1answer
189 views
Three (do)s in a Clojure method
I'm new to Clojure. How can I make this more idiomatic Clojure code? Among other things, there are three (do) blocks and I don't think using (def) as many times as I do is a recommended idea.
(defn ...
4
votes
1answer
232 views
A crude clojure progress reporting function
Please review this newbie's clojure code (mine). The purpose of this function is to report processing progress to the terminal. It loops through an array of maps that contain two properties: ...
3
votes
1answer
188 views
Clojure: lazy look and say sequence
I have been solving a set of online Clojure problems, one of them involves the look and say sequence. I have some working code:
(defn look-and-say [s]
(let [las (loop [item (first s) coll s ...
1
vote
3answers
98 views
From enumerator to map
I have an mail object that returns its headers as an Enumerator of Header objects, which have two methods, getName and getValue. I need to convert that to a nice Clojure map so I wrote this short ...
6
votes
4answers
307 views
How can I improve this code?
How can I improve this clojure code? It looks strange to me to have two recurs in the if.
It solves the following problem.
The following text is an in-order traversal of a binary tree with 1023 ...
3
votes
2answers
304 views
How can I improve this code?
The following code solves this problem:
The 3072 characters below contain a sequence of 5 characters which is repeated. However, there is a twist: one of the sequences has a typo. To be specific, ...
5
votes
4answers
544 views
Clojure — partitioning strings into substrings of fixed length
Hey all, I've got a clojure function here that's meant to parse a string of form
"DDXXXYYY"
where DD is meant to be discarded, and XXX and YYY are string representations of integers. Here's my ...
9
votes
3answers
366 views
Reservoir Sampling in Clojure
I am learning clojure and decided to start out by trying to write a solution to a fairly simple algorithm, reservoir sampling. As I stated, I am learning clojure specifically and problem solving in a ...
12
votes
4answers
893 views
Project Euler Problem 2 in Clojure
I am in the process of learning Clojure. I am fairly new to functional programming and would like to know if my code smells or if there are any performance implications with my approach.
; Returns ...
