qoelet

import Data.Char

-- frequencies based on large number of text
table :: [Float]
table = [8.2,1.5,2.8,4.3,12.7,2.2,2.0,6.1,7.0,0.2,0.8,4.0,2.4,6.7,7.5,1.9,0.1,6.0,6.3,9.1,2.8,1.0,2.4,0.2,2.0,0.1]

-- earlier functions in the chapter required here
lowers :: String -> Int
lowers xs = length [ x | x <- xs, isLower x]

qoelet

-- standard library version
replicate        :: Int -> a -> [a]
replicate n x    =  take n (repeat x)

-- my version (having to use list comprehension)
replicate'       :: Int -> a -> [a]
replicate' n x   = [x | xn <- [1..n]]

qoelet

-- λ <name> <expression>

-- lambda forms for myLast and myInit, tested with example list [1,2,3,4]
(\x -> head (reverse x))[1,2,3,4]

(\x -> take (length x - 1) x) [1,2,3,4]

qoelet

-- file: Fib.hs
-- Task: Generate first n Fibonacci numbers, then sum it

-- fib: given n for the index of the Fibonacci series, return the corresponding value, e.g. fib 9 gives 34
fib :: Int -> Int 

fib 0 = 0 
fib 1 = 1 
fib n = fib (n-1) + fib (n-2)

qoelet

-- file: myInit.hs
-- 2 ways to define init function (removes last element from a non empty list)

myInitOne :: [a] -> [a]

myInitOne [x] = []
myInitOne (x:xs) = [x] ++ myInitOne xs


myInitTwo :: [a] -> [a]

qoelet

-- file: myLast.hs

myLast :: [a] -> a

myLast x = head (reverse x)

qoelet

-- file: Clean.hs
-- removes null characters

import System.Environment (getArgs)

removeNull :: [Char] -> [Char]
removeNull [] = []
removeNull (x:xs)
    | x == '\000' = [] ++ removeNull xs
    | otherwise = [x] ++ removeNull xs

qoelet

-- file: Clean.hs
-- removes null characters

import System.Environment (getArgs)

removeNull :: [Char] -> [Char]
removeNull [] = []
removeNull (x:xs)
    | x == '\000' = [] ++ removeNull xs
    | otherwise = [x] ++ removeNull xs

qoelet

Sort  (cost=3357.35..3380.23 rows=9150 width=809) (actual time=147.963..159.258 rows=9429 loops=1)
   Sort Key: news_article.date_is_published
   Sort Method:  quicksort  Memory: 9491kB
   ->  Hash Join  (cost=828.56..2755.30 rows=9150 width=809) (actual time=38.766..107.775 rows=9429 loops=1)
# additional details etc etc.

qoelet

[Thu Jun 14 16:57:24 2012] [error] [client 127.0.0.1] mod_wsgi (pid=10827): Exception occurred processing WSGI script '/home/kenny/someapp/wsgi.py'.                                                                                                                                  
[Thu Jun 14 16:57:24 2012] [error] [client 127.0.0.1] Traceback (most recent call last):                                                        
[Thu Jun 14 16:57:24 2012] [error] [client 127.0.0.1]   File "/usr/lib/pymodules/python2.6/django/core/handlers/wsgi.py", line 230, in __call__ 
[Thu Jun 14 16:57:24 2012] [error] [client 127.0.0.1]     self.load_middleware()                                                                
[Thu Jun 14 16:57:24 2012] [error] [client 127.0.0.1]   File "/usr/lib/pymodules/python2.6/django/core/handlers/base.py", line 42, in load_middleware                                                                                                                                           
[Thu Jun 14 16:57:24