Tutorial by Examples: d

### Definition proc myproc {alpha {beta {}} {gamma green}} { puts [list $alpha $beta $gamma] } ### Use myproc A # => A {} green myproc A B # => A B green myproc A B C # => A B C This procedure accepts one, two, or three arguments: those parameters whose names are the fi...

proc myproc args { ... } proc myproc {args} { ... } ;# equivalent If the special parameter name args is the last item in the argument list, it receives a list of all arguments at that point in the command line. If there are none, the list is empty. There can be arguments, including optional one...

proc myproc {varName alpha beta} { upvar 1 $varName var set var [expr {$var * $alpha + $beta}] } set foo 1 myproc foo 10 5 puts $foo # => 15 In this particular case, the procedure is given the name of a variable in the current scope. Inside a Tcl procedure, such variables aren't...

Variables in Visual Basic are declared using the Dim keyword. For example, this declares a new variable called counter with the data type Integer: Dim counter As Integer A variable declaration can also include an access modifier, such as Public, Protected, Friend, or Private. This works in conju...

# application.rb config.time_zone = 'Eastern Time (US & Canada)'

# application.rb config.time_zone = 'Eastern Time (US & Canada)' config.active_record.default_timezone = :local

This is the code for changing output application file name (.apk). The name can be configured by assigning a different value to newName android { applicationVariants.all { variant -> def newName = "ApkName"; variant.outputs.each { output -> def ...

If you are optimizing all images manually, disable APT Cruncher for a smaller APK file size. android { aaptOptions { cruncherEnabled = false } }

In some cases it is necessary to calculate a variable amount of values on separate Futures. Assume to have a List[Future[Int]], but instead a List[Int] needs to be processed. Then the question is how to turn this instance of List[Future[Int]] into a Future[List[Int]]. For this purpose there is the s...

Creating a namedtuple with type hints is done using the function NamedTuple from the typing module: import typing Point = typing.NamedTuple('Point', [('x', int), ('y', int)]) Note that the name of the resulting type is the first argument to the function, but it should be assigned to a variable ...

Keeping a GUI responsive while running a lengthy process requires either some very elaborate "callbacks" to allow the GUI to process its message queue, or the use of (background) (worker) threads. Kicking off any number of threads to do some work usually isn't a problem. The fun starts wh...

PostgreSQL is an actively developed and mature open source database. Using the psycopg2 module, we can execute queries on the database. Installation using pip pip install psycopg2 Basic usage Lets assume we have a table my_table in the database my_database defined as follows. idfirst_namelast_n...

Loops can be nested, to preform iterated task within another iterated task. Consider the following loops: ch = 'abc'; m = 3; for c = ch for k = 1:m disp([c num2str(k)]) % NUM2STR converts the number stored in k to a charachter, % so it can be concatanet...

Finally, we want to get some of our dynamic data to be stored offline. meteor add ground:db Lists = new Meteor.Collection("lists"); GroundDB(Lists); Todos = new Meteor.Collection("todos") GroundDB(Todos);

The first step to logging is simply to run Meteor from the shell, and you'll get the server logs in the command console. meteor The next step is to pipe the contents of std_out and std_err to a logfile, like so: meteor > my_app_log.log 2> my_app_err.log

Once you have your server side logging in place, it's time to hop over to the client side. If you haven't explored the console API, be prepared for a treat. There's actually all sorts of things that you can do with the built in Console API that's native to every Chrome and Safari installation. So mu...

Once you have both your server-side logging running, and your client side development tools, you can start looking at Meteor specific extensions like the Meteor Chrome DevTools Extension. This lets you actually observe server logging in the client! Because the database is everywhere. As is logging. ...

The following example is from 0.5 - 0.7 days, and illustrates how to log an error when the database hasn't populated the client side cursor yet. Template.landingPage.postsList = function(){ try{ return Posts.find(); }catch(error){ //color code the error (red) console.error(erro...

The following uses the Chrome Logging API. If the .group() syntax is used in multiple templates, it will graphically organize the console logs from different templates into a hierarchical tree. You can also see how to inspect the current data context, and how to stringify data. Template.landingPa...

Simple example of using the Chrome Logging API. Template.landingPage.events({ 'click .selectItemButton':function(){ // color code and count the user interaction (blue) console.count('click .selectItemButton'); } });