Tutorial by Examples: p

A good way to learn about Elm is to try writing some expressions in the REPL (Read-Eval-Print Loop). Open a console in your elm-app folder (that you have created in the Initialize and build phase) and try the following: $ elm repl ---- elm-repl 0.17.1 ----------------------------------------------...

> List.repeat 3 "abc" ["abc","abc","abc"] : List String You can give List.repeat any value: > List.repeat 2 {a = 1, b = (2,True)} [{a = 1, b = (2,True)}, {a = 1, b = (2,True)}] : List {a : Int, b : (Int, Bool)}

List.sortWith allows you to sort lists with data of any shape - you supply it with a comparison function. compareBools : Bool -> Bool -> Order compareBools a b = case (a,b) of (False, True) -> LT (True, False) -> GT _ -> ...

sample on price increases: UPDATE ItemPrice SET Price = Price * CASE ItemId WHEN 1 THEN 1.05 WHEN 2 THEN 1.10 WHEN 3 THEN 1.15 ELSE 1.00 END

You may have noticed that many applications have double-back-click functionality to exit the app. In this example, we are overriding the default back button action using the onBackPressed() method override. This method will Toast a message for the single back-click action, and will close the app if...

We can get facts (ansible_os_family, ansible_pkg_mgr) with Ad-Hoc command of setup module and filter. ansible_os_family: $ ansible all -m setup -a 'filter=ansible_os_family' ra.local | SUCCESS => { "ansible_facts": { "ansible_os_family": "Debi...

Paramorphisms model primitive recursion. At each iteration of the fold, the folding function receives the subtree for further processing. para :: Functor f => (f (Fix f, a) -> a) -> Fix f -> a para f = f . fmap (\x -> (x, para f x)) . unFix The Prelude's tails can be modelled as ...

Apomorphisms model primitive corecursion. At each iteration of the unfold, the unfolding function may return either a new seed or a whole subtree. apo :: Functor f => (a -> f (Either (Fix f) a)) -> a -> Fix f apo f = Fix . fmap (either id (apo f)) . f Note that apo and para are dual...

Only the homepage works, all other pages return 404 Make sure mod_rewrite module has been installed in Apache and been enabled to load. See step 2 for info on how to do this here: https://www.digitalocean.com/community/tutorials/how-to-set-up-mod_rewrite-for-apache-on-ubuntu-14-04 Make sure the y...

<?php class MyClass { ... } class OtherClass { ... } ?> Any class that has the same name as it's file name will be auto loaded by Silverstripe. OtherClass will be loaded too because it is in a file which is being read. MyPage.php <?php class MyPage_Controller e...

Profiling string concatanation: In [1]: import string In [2]: %%timeit s=""; long_list=list(string.ascii_letters)*50 ....: for substring in long_list: ....: s+=substring ....: 1000 loops, best of 3: 570 us per loop In [3]: %%timeit long_list=list(string.ascii_letters)*50...

The source code with @profile directive before the function we want to profile: import requests @profile def slow_func(): s = requests.session() html=s.get("https://en.wikipedia.org/").text sum([pow(ord(x),3.1) for x in list(html)]) for i in range(50): s...

Editing the width of Separator Lines You can set make your table view's separator lines extend the to various widths across the table by changing the layoutMargins: property on your cell(s). This can be achieved in a number of ways. Changing the Separator Lines for specific cells In either your t...

Description An image maps is an image with clickable areas that usually act as hyperlinks. The image is defined by the <img> tag, and the map is defined by a <map> tag with <area> tags to denote each clickable area. Use the usemap and name attributes to bind the image and the map...

The var keyword allows a programmer to implicitly type a variable at compile time. var declarations have the same type as explicitly declared variables. var squaredNumber = 10 * 10; var squaredNumberDouble = 10.0 * 10.0; var builder = new StringBuilder(); var anonymousObject = new { One =...

Copying a partial array with the static Array.Copy() method, beginning at index 0 in both, source and destination: var sourceArray = new int[] { 11, 12, 3, 5, 2, 9, 28, 17 }; var destinationArray= new int[3]; Array.Copy(sourceArray, destinationArray, 3); // destinationArray will have 11,12 and...

Sometimes we need to make a lot of POST requests to one or many different endpoints. To deal with this scenario, we can use multi_curl. First of all, we create how many requests as needed exactly in the same way of the simple example and put them in an array. We use the curl_multi_init and add eac...

Following the 'Form Request Validation' example, the same Request Class can be used for POST, PUT, PATCH so you do not have to create another class using the same/similar validations. This comes in handy if you have attributes in your table that are unique. /** * Get the validation rules that a...

Just like most other C-style languages, each statement is terminated with a semicolon. Also, a closing tag is used to terminate the last line of code of the PHP block. If the last line of PHP code ends with a semicolon, the closing tag is optional if there is no code following that final line of co...

Subscripts can be used to simplify retrieving and setting elements in an array. Given the following array NSArray *fruit = @[@"Apples", @"Bananas", @"Cherries"]; This line [fruit objectAtIndex: 1]; Can be replaced by fruit[1]; They can also be used to set an...