Tutorial by Examples: t

DROP INDEX ix_cars_employee_id ON Cars; We can use command DROP to delete our index. In this example we will DROP the index called ix_cars_employee_id on the table Cars. This deletes the index entirely, and if the index is clustered, will remove any clustering. It cannot be rebuilt without rec...

Abstract factory pattern provides a way to obtain an coherent collection of objects through a collection of factories functions. As for every pattern, coupling is reduced by abstracting the way a set of objects are created, so that the user code is unaware of the many details of the objects he needs...

Factories can be used in conjunction with Inversion of Control (IoC) libraries too. The typical use case for such a factory is when we want to create an object based on parameters that are not known until run-time (such as the current User). In these cases it can be sometimes be difficult (if no...

Enumerating dictionaries allows you to run a block of code on each dictionary key-value pair using the method enumerateKeysAndObjectsUsingBlock:(void (^)(id key, id obj, BOOL *stop))block Example: NSDictionary stockSymbolsDictionary = @{ @"AAPL":...

In [1]: import numpy as np In [2]: import pandas as pd In [3]: df = pd.DataFrame({'A': list('XYZXYZXYZX'), 'B': [1, 2, 1, 3, 1, 2, 3, 3, 1, 2], 'C': [12, 14, 11, 12, 13, 14, 16, 12, 10, 19]}) In [4]: df.groupby('A')['B'].agg({'mean': np.mean, 'standard deviatio...

Given a file file.txt with the following content: line 1 line 2 line 3 You can delete a line from file content with the d command. The pattern to match is surrounded with default / delimiter and the d command follows the pattern: sed '/line 2/d' file.txt The above command will output: l...

Whenever you declare a new rule inside another rule it is called nesting. With basic nesting, as shown below, the nested selector will be compiled as a new CSS selector with all its parents prepended, separated by a space. // SCSS .parent { margin: 1rem; .child { float: left; } ...

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] ...

Singletons are used to ensure that only one instance of an object is being created. The singleton allows only a single instance of itself to be created which means it controls its creation. The singleton is one of the Gang of Four design patterns and is a creational pattern. Thread-Safe Singleton ...

Fourier Transform is probably the first lesson in Digital Signal Processing, it's application is everywhere and it is a powerful tool when it comes to analyze data (in all sectors) or signals. Matlab has a set of powerful toolboxes for Fourier Transform. In this example, we will use Fourier Transfor...

If you set opacity on an element it will affect all its child elements. To set an opacity just on the background of an element you will have to use RGBA colors. Following example will have a black background with 0.6 opacity. /* Fallback for web browsers that don't support RGBa */ background-color...

Objective-C [mySwitch setOn:YES]; //or [mySwitch setOn:YES animated:YES]; Swift mySwitch.setOn(false) //or mySwitch.setOn(false, animated: false)

Objective-C mySwitch.backgroundColor = [UIColor yellowColor]; [mySwitch setBackgroundColor: [UIColor yellowColor]]; mySwitch.backgroundColor =[UIColor colorWithRed:255/255.0 green:0/255.0 blue:0/255.0 alpha:1.0]; mySwitch.backgroundColor= [UIColor colorWithWhite: 0.5 alpha: 1.0]; mySwitch.backg...

Objective-C //for off-state mySwitch.tintColor = [UIColor blueColor]; [mySwitch setTintColor: [UIColor blueColor]]; //for on-state mySwitch.onTintColor = [UIColor cyanColor]; [mySwitch setOnTintColor: [UIColor cyanColor]]; Swift //for off-state mySwitch.tintColor = UIColor.blueColor() ...

If your project depends on the external libraries, you should first install them with opam. Assuming your dependencies are foo and bar and the main entry point of your project is foobar.ml you can then build a bytecode executable with ocamlbuild -use-ocamlfind -pkgs 'foo,bar' foobar.byte Warnin...

If your project has no external dependency and has foo.ml as its main entry point, you can compile a bytecode version with ocamlbuild foo.byte To get a native executable, run ocamlbuild foo.native

import pandas as pd import numpy as np df = pd.DataFrame({'A':[1,2,np.nan,3,np.nan], 'B':[1.2,7,3,0,8]}) df['C'] = df.A.interpolate() df['D'] = df.A.interpolate(method='spline', order=1) print (df) A B C D 0 1.0 1.2 1.0 1.000000 1 2.0 7.0 2...

Fortran 2003 introduced language features which can guarantee interoperability between C and Fortran (and to more languages by using C as an intermediary). These features are mostly accessed through the intrinsic module iso_c_binding: use, intrinsic :: iso_c_binding The intrinsic keyword here en...

The bind attribute can also be applied to derived types: geese.h struct Goose { int flock; float buoyancy; } struct Goose goose_c; geese.f90 use, intrinsic :: iso_c_binding, only : c_int, c_float type, bind(C) :: goose_t integer(c_int) :: flock real(c_float) :: buoyancy e...

For annotating some point of interest on map, we use pin annotation. Now, start by creating annotation object first. MKPointAnnotation *pointAnnotation = [[MKPointAnnotation alloc] init]; Now provide coordinate to pointAnnotation,as CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake...