Tutorial by Examples: pt

Swallowing Exceptions One should always re-throw exception in the following way: try { ... } catch (Exception ex) { ... throw; } Re-throwing an exception like below will obfuscate the original exception and will lose the original stack trace. One should never do this! The st...

Who says you cannot throw multiple exceptions in one method. If you are not used to playing around with AggregateExceptions you may be tempted to create your own data-structure to represent many things going wrong. There are of course were another data-structure that is not an exception would be mor...

Descriptive statistics (mean, standard deviation, number of observations, minimum, maximum, and quartiles) of numerical columns can be calculated using the .describe() method, which returns a pandas dataframe of descriptive statistics. In [1]: df = pd.DataFrame({'A': [1, 2, 1, 4, 3, 5, 2, 3, 4, 1],...

Optional parameters can be specified after required parameters, by using &OPTIONAL keyword. There may be multiple optional parameters after it. (defun foobar (x y &optional z) (format t "X (~s) and Y (~s) are required.~@ Z (~s) is optional.~%" x y z)) ...

page = PAGE page.10 = TEXT page.10.value = HELLO WORLD Usually this typoScript snippets are added to Web >> Template >> Info/Modify >> setup This snippet opens a new PAGE object. Inside the PAGE object, the 10th entry is set to be a TEXT object. The value of thus TEXT object ...

string nullString = null; string emptyString = ""; string whitespaceString = " "; string tabString = "\t"; string newlineString = "\n"; string nonEmptyString = "abc123"; bool result; result = String.IsNullOrEmpty(nullString); ...

If you want to use your own templates (be it HTML, XML, JSON or any other format) for a TYPO3 extension using fluid templating, you can add additional template paths. An extensions template/partial/layout paths are usually set in TypoScript setup under the properties plugin.tx_<extensionkey>...

If you want to display to your users meaningful errors instead of simple "sorry, something went wrong", Rails has a nice utility for the purpose. Open the file app/controllers/application_controller.rb and you should find something like this: class ApplicationController < ActionContro...

Each pair in the dictionary is an instance of KeyValuePair with the same type parameters as the Dictionary. When you loop through the dictionary with For Each, each iteration will give you one of the Key-Value Pairs stored in the dictionary. For Each kvp As KeyValuePair(Of String, String) In curren...

The caption-side property determines the vertical positioning of the <caption> element within a table. This has no effect if such element does not exist. Below an example with two tables with different values set to the caption-side property: The table on the left has caption-side: top whi...

Nesting is a very powerful feature, but should be used with caution. It can happen quite easily and quickly, that you start nesting and carry on including all children in a nest, of a nest, of a nest. Let me demonstrate: // SCSS header { // [css-rules] .holder { // [css-rules] ...

To illustrate the effect of good for loop construction, we will calculate the mean of each column in four different ways: Using a poorly optimized for loop Using a well optimized for for loop Using an *apply family of functions Using the colMeans function Each of these options will be shown...

Install Codeception: composer global status composer global require "codeception/codeception=~2.0.0" "codeception/specify=*" "codeception/verify=*" Install Faker: cd /var/www/yii // Path to your application composer require --de...

The following example encrypts data by using a hybrid cryptosystem consisting of AES GCM and OAEP, using their default parameter sizes and an AES key size of 128 bits. OAEP is less vulnerable to padding oracle attacks than PKCS#1 v1.5 padding. GCM is also protected against padding oracle attacks. ...

By default you will get de codes and id's for optionsets and lookups. If you want to get the label as well, you need to add an extra header to the call. $.ajax({ url: Xrm.Page.context.getClientUrl() + '/api/data/v8.0/contacts', headers: { 'Accept': 'Application/json', ...

To document a function, it is often helpful to have an example script which uses your function. The publish function in Matlab can then be used to generate a help file with embedded pictures, code, links, etc. The syntax for documenting your code can be found here. The Function This function uses ...

Incorrect usage: In the following snippet, the last match will never be used: let x = 4 match x with | 1 -> printfn "x is 1" | _ -> printfn "x is anything that wasn't listed above" | 4 -> printfn "x is 4" prints x is anything that wasn't listed abov...

The use of null values is strongly discouraged, unless interacting with legacy Java code that expects null. Instead, Option should be used when the result of a function might either be something (Some) or nothing (None). A try-catch block is more appropriate for error-handling, but if the function ...

Following code will release the lock. There will be no problem. Behind the scenes lock statement works as try finally lock(locker) { throw new Exception(); } More can be seen in the C# 5.0 Specification: A lock statement of the form lock (x) ... where x is an expression of a referenc...

$ pg_dumpall -f backup.sql This works behind the scenes by making multiple connections to the server once for each database and executing pg_dump on it. Sometimes, you might be tempted to set this up as a cron job, so you want to see the date the backup was taken as part of the filename: $ post...