Tutorial by Examples: b

For example, if t1 is currently not an InnoDB table, this statement changes its storage engine to InnoDB: ALTER TABLE t1 ENGINE = InnoDB; If the table is already InnoDB, this will rebuild the table and its indexes and have an effect similar to OPTIMIZE TABLE. You may gain some disk space improv...

x = tf.constant(1.) bool = tf.constant(True) res = tf.cond(bool, lambda: tf.add(x, 1.), lambda: tf.add(x, 10.)) # sess.run(res) will give you 2.

Below won't work on a Windows machine $file = $request->file('file_upload'); $sampleName = 'UserUpload'; $destination = app_path() . '/myStorage/'; $fileName = $sampleName . '-' . date('Y-m-d-H:i:s') . '.' . $file->getClientOriginalExtension(); $file->move($destination, $fileName); ...

Thread synchronization can be accomplished using mutexes, among other synchronization primitives. There are several mutex types provided by the standard library, but the simplest is std::mutex. To lock a mutex, you construct a lock on it. The simplest lock type is std::lock_guard: std::mutex m; vo...

This query gets all books with ratings greater than or equal to zero and less than six. all_books = Book.objects.filter(ratings_range_contained_by=(0, 6))

This query selects all books with any rating greater than or equal to four. maybe_good_books = Books.objects.filter(ratings_range__contains=(4, None))

A closure is the PHP equivalent of an anonymous function, eg. a function that does not have a name. Even if that is technically not correct, the behavior of a closure remains the same as a function's, with a few extra features. A closure is nothing but an object of the Closure class which is create...

It is possible, inside a closure, to use an external variable with the special keyword use. For instance: <?php $quantity = 1; $calculator = function($number) use($quantity) { return $number + $quantity; }; var_dump($calculator(2)); // Shows "3" You can go further by ...

As seen previously, a closure is nothing but an instance of the Closure class, and different methods can be invoked on them. One of them is bindTo, which, given a closure, will return a new one that is bound to a given object. For example: <?php $myClosure = function() { echo $this->p...

Let's consider this example: <?php $myClosure = function() { echo $this->property; }; class MyClass { public $property; public function __construct($propertyValue) { $this->property = $propertyValue; } } $myInstance = new MyClass('Hello world...

Since PHP7, it is possible to bind a closure just for one call, thanks to the call method. For instance: <?php class MyClass { private $property; public function __construct($propertyValue) { $this->property = $propertyValue; } } $myClosure = function() ...

In general, an observer is a class with a specific method being called when an action on the observed object occurs. In certain situations, closures can be enough to implement the observer design pattern. Here is a detailed example of such an implementation. Let's first declare a class whose purpos...

We define two sets a and b >>> a = {1, 2, 2, 3, 4} >>> b = {3, 3, 4, 4, 5} NOTE: {1} creates a set of one element, but {} creates an empty dict. The correct way to create an empty set is set(). Intersection a.intersection(b) returns a new set with elements present in bot...

This example creates a simple 1-column repeater that displays a list of numbers, one per repeater item. Markup: <asp:Repeater ID="Repeater1" runat="server"> <ItemTemplate> <%# Container.DataItem.ToString() %> </ItemTemplate> </Repe...

git is fundamentally a key-value store. When you add data to git, it builds an object and uses the SHA-1 hash of the object's contents as a key. Therefore, any content in git can be looked up by it's hash: git cat-file -p 4bb6f98 There are 4 types of Object: blob tree commit tag

A commit is probably the object type most familiar to git users, as it's what they are used to creating with the git commit commands. However, the commit does not directly contain any changed files or data. Rather, it contains mostly metadata and pointers to other objects which contain the actual c...

A tree basically represents a folder in a traditional filesystem: nested containers for files or other folders. A tree contains: 0 or more blob objects 0 or more tree objects Just as you can use ls or dir to list the contents of a folder, you can list the contents of a tree object. $ git ca...

A blob contains arbitrary binary file contents. Commonly, it will be raw text such as source code or a blog article. But it could just as easily be the bytes of a PNG file or anything else. If you have the hash of a blob, you can look at it's contents. $ git cat-file -p d429810 package com.exampl...

The non-block do construct looks like integer i do 100, i=1, 5 100 print *, i That is, where the labelled termination statement is not a continue statement. There are various restrictions on the statement that can be used as the termination statement and the whole thing is generally v...

MySQL's DELETE statement can use the JOIN construct, allowing also to specify which tables to delete from. This is useful to avoid nested queries. Given the schema: create table people ( id int primary key, name varchar(100) not null, gender char(1) not null ); insert people (id,na...