I am passing a vector of hiccup to a funtion that just wraps it in more hiccup, but it does not return it as I would expect.
Here's an example of what I mean:
(defn wrap-fn
[input]
[div.content-box
[input]])
(defn main-fn
[vector-of-hiccup]
(foreach [hiccup from vector-of-hiccup]
(wrap-fn hiccup-from-list)))
How do I implement the made up foreach loop above?
I've tried to use 'apply' to apply the wrap-fn to each of the vector params but it only returns the first element wrapped. I've tried to creating all sorts of loops and I have similar levels of success.
I'm sure there is a way to do this, please help me find one that works.
You need something like this:
(defn wrap-fn
[input]
[:div.content-box
[input]]) ; <= you may not want to wrap `input` in a vector.
(defn main-fn
[vector-of-hiccup]
(vec
(for [item vector-of-hiccup]
(wrap-fn item))))
Note the : in :div. Hiccup vectors always start with a keyword. Also, since for returns a lazy sequence, you should convert it into a vector with vec.
Also, depending on your situation, you may want to have input instead of [input] under the :div.content-box.
See the Documentation section of the clj-template project for valuable learning information.
for an assignment I need to create a map from a text file in clojure, which I am new to. I'm specifically using a hash-map...but it's possible I should be using another type of map. I'm hoping someone here can answer that for me. I did try changing my hash-map to sorted-map but it gave me the same problem.
The first character in every line in the file is the key and the whole line is the value. The key is a number from 0-9999. There are 10,000 lines and each number after the first number in a line is a random number between 0 and 9999.
I've created the hashmap successfully I think. At least, its not giving me an error when I just run that code. However when I try to iterate through it, printing every value for keys 0-9999 it gives me a stack overflow error right at the middle of line 2764(in the text file). I'm hoping someone can tell me why it's doing this and a better way to do it?
Here's my code:
(ns clojure-project-441.core
(:gen-class))
(defn -main
[& args]
(def pages(def hash-map (file)))
(iter 0)
)
(-main)
(defn file []
(with-open [rdr (clojure.java.io/reader "pages.txt")]
(reduce conj [] (line-seq rdr))))
(defn iter [n]
(doseq [keyval (pages n)] (print keyval))
(if (< n 10000)
(iter (inc n))
)
)
here's a screenshot of my output
If it's relevant at all I'm using repl.it as my IDE.
Here are some screenshots of the text file, for clarity.
beginning of text file
where the error is being thrown
Thanks.
I think the specific problem that causes the exception to be thrown is caused because iter calls itself recursively too many times before hitting the 10,000 line limit.
There some issues in your code that are very common to all people learning Clojure; I'll try to explain:
def is used to define top-level names. They correspond with the concept of constants in the global scope on other programming languages. Think of using def in the same way you would use defn to define functions. In your code, you probably want to use let to give names to intermediate results, like:
(let [uno 1
dos 2]
(+ uno dos)) ;; returns 3
You are using the name hash-map to bind it to some result, but that will get in the way if you want to use the function hash-map that is used to create maps. Try renaming it to my-map or similar.
To call a function recursively without blowing the stack you'll need to use recur for reasons that are a bit long to explain. See the factorial example here: https://clojuredocs.org/clojure.core/recur
My advice would be to think of this assignment as a pipeline composed of the following small functions:
A function that reads the lines from the file (you already have this)
A function that, given a line, returns a pair: the first element of the pair is the first number of the line, the second element is the whole line (the input parameter) OR
A function that reads the first number of the line
To build the map, you have a few options; two off the top of my mind:
Use a loop construct and, for each line, "update" the hash-map to include a new key-value pair (the key is the first number, the value is the whole line), then return the whole hash-map you've built
Use a reduce operation: you create a collection of key-value pairs, then tell reduce to merge, one step at a time, into the original hash-map. The result is the hash-map you want
I think the key is to get familiar with the functions that you can use and build small functions that you can test in isolation and try to group them conveniently to solve your problem. Try to get familiar with functions like hash-map, assoc, let, loop and recur. There's a great documentation site at https://clojuredocs.org/ that also includes examples that will help you understand each function.
I'm unable to figure out why my code isn't working despite looking through answers to similar questions. I'm too new at Prolog to properly name things, but I hope you can see what I'm trying to get at.
I am defining a timetable roughly based on this program and am struggling with getting a list of the Classes that Mike teaches for a given result (Next step will be to declare that only results where both Mike and Phil teach 2 should be returned, but I want to work through it so that I can see and understand what's going on).
I imagine this should be simple but any combinations of the addToList(List,C) predicate never work. I know there is the append predicate but I hear it's inefficient, and would like to learn the 'raw' way. I don't know how many variations I've attempted and can't get my head around the way Prolog works in this regard and don't know on what level I'm going wrong - it's all a bit of a black box mystery working with it.
var program =
:- use_module(library(lists)).
prefers(may,a).
prefers(may,b).
prefers(may,c).
prefers(may,d).
prefers(bob,a).
prefers(bob,b).
prefers(bob,c).
prefers(pete,a).
prefers(pete,b).
prefers(pete,c).
prefers(pete,d).
prefers(tom,a).
prefers(tom,b).
prefers(tom,c).
prefers(tom,d).
teacher_pref(mike,a).
teacher_pref(mike,b).
teacher_pref(mike,c).
teacher_pref(phil,b).
teacher_pref(phil,c).
teacher_pref(phil,d).
addToList([C|List],C):- addToList(List,C).
timetable([a,[C1,S1,T1],b,[C2,S2,T2],c,[C3,S3,T3],d,[C4,S4,T4]],List1):-
teacher_pref(T1,C1),
teacher_pref(T2,C2),
teacher_pref(T3,C3),
teacher_pref(T4,C4),
prefers(S1,C1),
prefers(S2,C2),
S1\\=S2,
prefers(S3,C3),
S1\\=S3,
S2\\=S3,
prefers(S4,C4),
S1\\=S4,
S2\\=S4,
S3\\=S4,
addToList(List1,C):-
teacher_pref(mike,C).
session.consult( program );
session.query('timetable([C1,[a,S1,T1],C2,[b,S2,T2],C3,[c,S3,T3,L3],C4,[d,S4,T4]],List1).')
If I understand correctly you have:
teacher_pref(mike,a).
teacher_pref(mike,b).
teacher_pref(mike,c).
And you want to get a list of these classes, which would be:
[a, b, c]
In Prolog we have some higher-order predicates that are for occasions like this:
% (What to find, the goal to call, all the results)
?- findall(Class, teacher_pref(mike, Class), Classes).
Classes = [a, b, c].
In the Tau-Prolog docs they're under All Solutions, in SWI-Prolog there's a couple more.
To make this into a more generic predicate:
teacher_prefs(Teacher, Prefs) :-
findall(Pref, teacher_pref(Teacher, Pref), Prefs).
I am getting an error when I put in these two codes. I am using Stata 12.
I have recoded CHILDREN already as a dummy variable called CHILDRENDUMMY and the variable is located in the list of variables. I am trying to run two margins commands, but I am getting the error message
vsquish CHILDRENDUMMY not found in list of covariates
Can someone please help me?
First Code
margins, dydx (DISAGMT) at (CHILDRENDUMMY= (0 1)) vsquish
Second Code
margins, at dydx (DISAGMT= (0) CHILDRENDUMMY= (0 1)) vsquish
See http://www.stata.com/help.cgi?margins for current syntax.
You should see that you have confused margins on what you think is a covariate. For example, vsquish is an option, not a covariate. How did that happen?
The second syntax is not what you want, as at() needs an argument. That's like saying "meet me at" without time or place.
You don't say what you want to do, but my guess is more like
margins, dydx(DISAGMT) at(CHILDRENDUMMY=(0 1)) vsquish
Note that option names and their arguments should not be separated by spaces: the form is foobar(frog) not foobar (frog).
For future questions on Stata, knowing how to spell the software name is worth knowing: http://www.statalist.org/forums/help#spelling
For future questions, note the standard of complete self-contained examples that can be run by anyone with the software: https://stackoverflow.com/help/mcve
Im sure I have read somwhere how it is possible to use the reconciler to test query expressions in Om Next directly but im not able to find the source again or figure out if this is possible based on the Om documentation. Is this possible to do so and if it is, how?
What I have right now to test is using the parser but I was hoping for a better way using the reconciler:
(parser {:state (atom state)} (om/get-query MyQuery))
This is how I currently find the value of top level keywords:
(defn query [kw]
(let [res (my-parser {:state my-reconciler} `[[~kw _]])]
(when (not-empty res) (apply val res))))
So in your case you could try:
(my-parser {:state my-reconciler} (om/get-query MyQuery))
It looks like the value for :state can either be a state you give it as in your example, or the reconciler itself as in my example.
It depends on what you mean by "test query expressions in Om Next directly"? The code you wrote above is the only way to check how the parser will interpret the query you give it.
If you're wanting to see how the app state will be normalized and denormalized using the queries you provide, maybe the documentation for idents and om/tree->db is closer to what you're looking for.