How to handle recursive parent/child problems like this?

Posted by lsdude on Stack Overflow See other posts from Stack Overflow or by lsdude
Published on 2010-03-08T16:55:08Z Indexed on 2010/03/08 17:36 UTC
Read the original article Hit count: 182

Filed under:

recursion

|

ruby

|

php

In web dev I come across these problems a lot.

For example, we have a giant list of URLs that are in this format:

/businesses  
/businesses/food  
/businesses/food/wendys  
/businesses/food/wendys/chili  
/businesses/food/wendys/fries  
/businesses/food/wendys/chicken-nuggets  
/businesses/pharmacy/cvs  
/businesses/pharmacy/cvs/toothpaste  
/businesses/pharmacy/cvs/toothpaste/brand  
...

and then we need to output each one, where the parent category is in h1 tags, the child is in h2 tags, and the children of that are in h3 tags.

I can handle this but I feel my code is messy. I'm sure there is a design pattern I can use? Langs are ruby/php usually. how would you handle this?

© Stack Overflow or respective owner

Related posts about recursion

tail recursion vs. forward recursion

as seen on Stack Overflow - Search for 'Stack Overflow'
Can someone give me the difference between these two kinds recursions and example? specifically in ocaml. Thanks >>> More
Are there advantages for using recursion over iteration - other than sometimes readability and elegance?

as seen on Programmers - Search for 'Programmers'
I am about to make two assumptions. Please correct me if they're wrong: There isn't a recursive algorithm without an iterative equivalent. Iteration is always cheaper performance-wise than recursion (at least in general purpose languages such as Java, C++, Python etc.). If it's true that recursion… >>> More
Python recursive function error: "maximum recursion depth exceeded"

as seen on Stack Overflow - Search for 'Stack Overflow'
I solved Problem 10 of Project Euler with the following code, which works through brute force: def isPrime(n): for x in range(2, int(n**0.5)+1): if n % x == 0: return False return True def primeList(n): primes = [] for i in range(2,n): if isPrime(i): … >>> More
Dynamic Programming Recursion and a sprinkle of Memoization

as seen on Stack Overflow - Search for 'Stack Overflow'
I have this massive array of ints from 0-4 in this triangle. I am trying to learn dynamic programming with Ruby and would like some assistance in calculating the number of paths in the triangle that meet three criterion: You must start at one of the zero points in the row with 70 elements. Your… >>> More
How does the recursion here work?

as seen on Stack Overflow - Search for 'Stack Overflow'
code 1: public static int fibonacci (int n){ if (n == 0 || n == 1) { return 1; } else { return fibonacci (n-1) + fibonacci (n-2); } } how can you use fibonacci if you haven't gotten done explaining what it is yet? I've been able to understand… >>> More

Related posts about ruby

Setting up Rails to work with sqlserver

as seen on Stack Overflow - Search for 'Stack Overflow'
Ok I followed the steps for setting up ruby and rails on my Vista machine and I am having a problem connecting to the database. Contents of database.yml development: adapter: sqlserver database: APPS_SETUP Host: WindowsVT06\SQLEXPRESS Username: se Password: paswd Run rake db:migrate… >>> More
marshal data too short!!!

as seen on Stack Overflow - Search for 'Stack Overflow'
My application requires to keep large data objects in session. There are like 3-4 data objects each created by parsing a csv containing 150 X 20 cells having strings of 3-4 characters. My application shows this error- "marshal data too short". I tried this- Deleting the old session table. Deleting… >>> More
Sinatra and XML POST request

as seen on Stack Overflow - Search for 'Stack Overflow'
I don't know is it my mistake or no. So i have that code: <code> post '/singin/get_token' do content_type :xml puts request.body.read puts xmlRequest xmlRequest = REXML::Document.new(request.body.read) ... </code> And when i post something like that: <code> <?xml… >>> More
how to change ruby path from /usr/bin/ruby to /usr/local/bin/ruby

as seen on Stack Overflow - Search for 'Stack Overflow'
reading around the various ruby install tutorials it's required to change path from /usr/bin/ruby to /usr/local/bin/ruby but i cant seem to be able to do it. Ultimately i want to install Ruby 1.9.2, should i uninstall 1.8.7 or what? i tried to install Ruby 1.9.2 with macports, the installation seemed… >>> More
strange bundler error: tar_input.rb:49:in `initialize': not in gzip format (Zlib::GzipFile::Error) o

as seen on Stack Overflow - Search for 'Stack Overflow'
i am getting a strange bundler error when running bundle pack with bundler 0.9.12 any ideas? (see pastie for a better formatted code: http://pastie.org/881328 ) /opt/ruby-enterprise-1.8.7-2010.01/lib/ruby/site_ruby/1.8/rubygems/package/tar_input.rb:49:in `initialize': not in gzip format (Zlib::GzipFile::Error) … >>> More