Tutorial by Examples: b

To make a custom pipe available application wide, During application bootstrap, extending PLATFORM_PIPES. import { bootstrap } from '@angular/platform-browser-dynamic'; import { provide, PLATFORM_PIPES } from '@angular/core'; import { AppComponent } from './app.component'; import { MyPipe }...

Sometimes when you make a game you need to create and destroy a lot of objects of the same type over and over again. You can simply do this by making a prefab and instantiate/destroy this whenever you need to, however, doing this is inefficient and can slow your game down. One way to get around thi...

In oracle, the difference (in days and/or fractions thereof) between two DATEs can be found using subtraction: SELECT DATE '2016-03-23' - DATE '2015-12-25' AS difference FROM DUAL; Outputs the number of days between the two dates: DIFFERENCE ---------- 89 And: SELECT TO_DATE( '201...

A browser's debugging console can be used in order to print simple messages. This debugging or web console can be directly opened in the browser (F12 key in most browsers – see Remarks below for further information) and the log method of the console Javascript object can be invoked by typing the fol...

pg_dump -Fc -f DATABASE.pgsql DATABASE The -Fc selects the "custom backup format" which gives you more power than raw SQL; see pg_restore for more details. If you want a vanilla SQL file, you can do this instead: pg_dump -f DATABASE.sql DATABASE or even pg_dump DATABASE > DATABA...

psql < backup.sql A safer alternative uses -1 to wrap the restore in a transaction. The -f specifies the filename rather than using shell redirection. psql -1f backup.sql Custom format files must be restored using pg_restore with the -d option to specify the database: pg_restore -d DATABA...

$ 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...

Think about a situation where we need to callback a function with arguments. std::function used with std::bind gives a very powerful design construct as shown below. class A { public: std::function<void(int, const std::string&)> m_CbFunc = nullptr; void foo() { ...

Assumptions for this example: You have a class, foo.bar.Baz. You'd like to create a run configuration that runs the main method. It's in a module called fooBar. In your gradle file: idea { workspace.iws.withXml { provider -> // I'm not actually sure why this is necessar...

Show the changes between the tip of new and the tip of original: git diff original new # equivalent to original..new Show all changes on new since it branched from original: git diff original...new # equivalent to $(git merge-base original new)..new Using only one parameter such as ...

This is the most basic version of a trait in Scala. trait Identifiable { def getIdentifier: String def printIndentification(): Unit = println(getIdentifier) } case class Puppy(id: String, name: String) extends Identifiable { def getIdentifier: String = s"$name has id $id" } ...

${parameter:-word} If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted. $ unset var $ echo "${var:-XX}" # Parameter is unset -> expansion XX occurs XX $ var="" # Parameter is null ...

The semantics for this are similar to that of default value substitution, but instead of substituting a default value, it errors out with the provided error message. The forms are ${VARNAME?ERRMSG} and ${VARNAME:?ERRMSG}. The form with : will error our if the variable is unset or empty, whereas the ...

Shortest match: $ a='I am a string' $ echo "${a#*a}" m a string Longest match: $ echo "${a##*a}" string

You can use buffers to work with multiple files. When you open a file using :e path/to/file it opens in a new buffer (the command means edit the file). New buffer that holds a temporary copy of the file. You can go to previous buffer with :bp[rev] and next buffer with :bn[ext]. You can go to a...

If you want to see the generated bytecode for a Java program, you can use the provided javap command to view it. Assuming that we have the following Java source file: package com.stackoverflow.documentation; import org.springframework.stereotype.Service; import java.io.IOException; import j...

The ember data models have a toJSON method that extracts the relevant data: console.log(model.toJSON()); This method uses the JSONSerializer to create the JSON representation. If you want to log the data in a more app-specific way, you can use serialize: model.serialize(); which uses the se...

Ember has a static global method called runInDebug which can run a function meant for debugging. Ember.runInDebug(() => { // this code only runs in dev mode }); In a production build, this method is defined as an empty function (NOP). Uses of this method in Ember itself are stripped from ...

Schedulers are an RxJava abstraction about processing unit. A scheduler can be backed by a Executor service, but you can implement your own scheduler implementation. A Scheduler should meet this requirement : Should process undelayed task sequencially (FIFO order) Task can be delayed A Sched...

import pylab as plt import numpy as np plt.style.use('ggplot') fig = plt.figure(1) ax = plt.gca() # make some testing data x = np.linspace( 0, np.pi, 1000 ) test_f = lambda x: np.sin(x)*3 + np.cos(2*x) # plot the test data ax.plot( x, test_f(x) , lw = 2) # set the axis labels ax...