Tutorial by Examples: p

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...

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...

import pandas.io.sql import pyodbc import pandas as pd Specify the parameters # Parameters server = 'server_name' db = 'database_name' UID = 'user_id' Create the connection # Create the connection conn = pyodbc.connect('DRIVER={SQL Server};SERVER=' + server + ';DATABASE=' + db + '; UID...

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...

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] ...

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...

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...

order allow,deny deny from 255.0.0.0 allow from all This denies access to the IP 255.0.0.0. order allow,deny deny from 123.45.6. allow from all This denies access to all IPs in the range 123.45.6.0 to 123.45.6.255.

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...

In attempt to send a response asynchronously from chrome.runtime.onMessage callback we might try this wrong code: chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) { $.ajax({ url: 'https://www.google.com', method: 'GET', success: functio...

Homebrew You can install Node.js using the Homebrew package manager. Start by updating brew: brew update You may need to change permissions or paths. It's best to run this before proceeding: brew doctor Next you can install Node.js by running: brew install node Once Node.js is installe...

Detailed instructions on getting hdfs set up or installed.

Several values of the same type can be returned by passing an output iterator to the function. This is particularly common for generic functions (like the algorithms of the standard library). Example: template<typename Incrementable, typename OutputIterator> void generate_sequence(Increment...

Mapreduce is a part of Hadoop. So when Apache Hadoop (or any distribution of Hadoop is installed) MR is automatically installed. MapReduce is the data processing framework over HDFS(Hadoop distributed file system). MR jobs maybe written using Java, python, Scala, R, etc.

Null coalescing is a new operator introduced in PHP 7. This operator returns its first operand if it is set and not NULL. Otherwise it will return its second operand. The following example: $name = $_POST['name'] ?? 'nobody'; is equivalent to both: if (isset($_POST['name'])) { $name = $_P...

You can add protocols to standard classes to extends their functionality: @protocol EncodableToString <NSObject> - (NSString *)toString; @end @interface NSDictionary (XYZExtended) <EncodableToString> @end @implementation NSDictionary (XYZExtended) - (NSString *)toString { ...

Using filterUsingPredicate: This Evaluates a given predicate against the arrays content and return objects that match. Example: NSMutableArray *array = [NSMutableArray array]; [array setArray:@[@"iOS",@"macOS",@"tvOS"]]; NSPredicate *predicate = [N...