Tutorial by Examples: ch

Some common operations in MATLAB, like differentiation or integration, output results that have a different amount of elements than the input data has. This fact can easily be overlooked, which would usually cause errors like Matrix dimensions must agree. Consider the following example: t = 0:0.1:1...

//Get instance of cache using System.Runtime.Caching; var cache = MemoryCache.Default; //Check if cache contains an item with cache.Contains("CacheKey"); //get item from cache var item = cache.Get("CacheKey"); //get item from cache or add item if not existing obje...

These Java issues can be very embarrassing, and sometimes remain undiscovered until run in production. Fallthrough behavior in switch statements is often useful; however, missing a “break” keyword when such behavior is not desired can lead to disastrous results. If you have forgotten to put a “break...

For Each row As DataRow In FooDataTable.Rows Me.RowsToProcess.Add(row) Next Dim myOptions As ParallelOptions = New ParallelOptions() myOptions.MaxDegreeOfParallelism = environment.processorcount Parallel.ForEach(RowsToProcess, myOptions, Sub(currentRow, state) ...

ChoiceDialog allows the user to pick one item from a list of options. List<String> options = new ArrayList<>(); options.add("42"); options.add("9"); options.add("467829"); options.add("Other"); ChoiceDialog<String> dialog = new Choice...

The @each directive allows you to iterate through any list or map. It takes the form of @each $var or <list or map> {} where $var can be any variable name and <list or map> can be anything that returns a list or map. In the following example, the loop will iterate through the $authors l...

All we need to do is to use set() method of $query object. It takes two arguments, first what we want to set and second what value to set. add_action( 'pre_get_posts', 'change_posts_per_page' ); function change_posts_per_page( $query ) { if( !$query->is_main_query() || is_admin() ) retu...

Let's say you need to check if an email address appears in a long list of email addresses. Use the MATCH function to return the row number on which the email address can be found. If there is no match, the function returns an #N/A error. =MATCH(F2,$D$2:$D$200,0) The value you're retrieving ...

This will rollback both inserts due to an invalid datetime: BEGIN TRANSACTION BEGIN TRY INSERT INTO dbo.Sale(Price, SaleDate, Quantity) VALUES (5.2, GETDATE(), 1) INSERT INTO dbo.Sale(Price, SaleDate, Quantity) VALUES (5.2, 'not a date', 1) COMMIT TRANSACTION END TRY BEG...

Java SE 7 switch itself can not be parameterised to be case insensitive, but if absolutely required, can behave insensitive to the input string by using toLowerCase() or toUpperCase: switch (myString.toLowerCase()) { case "case1" : ... break; case &...

Let's say we have type ENUM('fish','mammal','bird') An alternative is type VARCHAR(20) COMENT "fish, bird, etc" This is quite open-ended in that new types are trivially added. Comparison, and whether better or worse than ENUM: (same) INSERT: simply provide the string (worse?)...

Changing an auto-increment value is useful when you don't want a gap in an AUTO_INCREMENT column after a massive deletion. For example, you got a lot of unwanted (advertisement) rows posted in your table, you deleted them, and you want to fix the gap in auto-increment values. Assume the MAX value o...

The angular.forEach accepts an object and an iterator function. It then runs the iterator function over each enumerable property/value of the object. This function also works on arrays. Like the JS version of Array.prototype.forEach The function does not iterate over inherited properties (prototype...

Transform tr = GetComponent<Transform>().Find("NameOfTheObject"); GameObject go = tr.gameObject; Find returns null if none is found ProsConsLimited, well defined search scopeStrings are weak references

ALTER TABLE fish_data.fish DROP PRIMARY KEY; ALTER TABLE fish_data.fish MODIFY COLUMN fish_id DECIMAL(20,0) NOT NULL PRIMARY KEY; An attempt to modify the type of this column without first dropping the primary key would result in an error.

Sometimes it's useful to be able to extend a class with new functions. For example let's suppose that a string should be converted to a camel case string. So we need to tell TypeScript, that String contains a function called toCamelCase, which returns a string. interface String { toCamelCase()...

# list gem sources: gem sources -l # remove default gem source: gem sources -r https://rubygems.org/ # add other gem sources: gem sources -a https://ruby.taobao.org/

XML <Goku> <child name="Gohan"/> <child name="Goten"/> </Goku> XPATH count(/Goku/child) OUTPUT 2.0

<?php $ch = curl_init(); //curl handler init curl_setopt($ch,CURLOPT_URL,"http://www.google.com/search?q=curl"); curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);// set optional params curl_setopt($ch,CURLOPT_HEADER, false); $result=curl_exec($ch); ...

You can register for notifications of when the device text size is changed. Swift NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(updateFont), name: name:UIContentSizeCategoryDidChangeNotification, object: nil) Objective-C [[NSNotificationCenter defaultCenter] addObs...