Tutorial by Examples: d

Such a group is made of radiobuttons that share a control variable so that no more than one can be selected. # control variable var = tk.IntVar(parent, 0) # group of radiobuttons for i in range(1,4): tk.Radiobutton(parent, text='Choice %i' % i, value=i, variable=var).pack() tk.Button(p...

Yank all lines containing TODO into a register by using append operation :global/TODO/yank A Here, we are searching for a TODO keyword globally, yanking all lines into register a (A register appends all lines to a register). NOTE: It is in general a good practice to clear a register before perf...

If constraints for std::promise and std::future are not met an exception of type std::future_error is thrown. The error code member in the exception is of type std::future_errc and values are as below, along with some test cases: enum class future_errc { broken_promise = /* the t...

How can I print hello world 5 times? 5.times{ println "hello world" }

Getting a GA Account: If you don’t have an Analytics account, create one. If you do have an Analytics account, sign in. Both options are available at google.com/analytics Setting up a property in your Analytics account: A property represents your website or app where the data gets aggrega...

The gross majority of the time a SyntaxError which points to an uninteresting line means there is an issue on the line before it (in this example, it's a missing parenthesis): def my_print(): x = (1 + 1 print(x) Returns File "<input>", line 3 print(x) ^...

The below coordinator job will trigger coordinator action once in a day that executes a workflow. The workflow has a shell script that moves input to output. <coordinator-app name="log_process_coordinator" frequency="${coord:days(1)}" start="2017-04-29T06:00Z" ...

Copy the script, coordinator.xml and workflow.xml into HDFS. coordinator.xml must be present in the directory specified by oozie.coord.application.path in job.properties. workflow.xml should be present in the directory specified by workflowAppUri. Once everything is in place, run the below command f...

Table/Column Names Two common ways of formatting table/column names are CamelCase and snake_case: SELECT FirstName, LastName FROM Employees WHERE Salary > 500; SELECT first_name, last_name FROM employees WHERE salary > 500; Names should describe what is stored in their object. Th...

There is no widely accepted standard. What everyone agrees on is that squeezing everything into a single line is bad: SELECT d.Name, COUNT(*) AS Employees FROM Departments AS d JOIN Employees AS e ON d.ID = e.DepartmentID WHERE d.Name != 'HR' HAVING COUNT(*) > 10 ORDER BY COUNT(*) DESC; At th...

Content of file.json (one JSON object per line): {"A": 1, "B": 2} {"A": 3, "B": 4} How to read directly from a local file: pd.read_json('file.json', lines=True) # Output: # A B # 0 1 2 # 1 3 4

if len(sys.argv) != 4: # The script name needs to be accounted for as well. raise RuntimeError("expected 3 command line arguments") f = open(sys.argv[1], 'rb') # Use first command line argument. start_line = int(sys.argv[2]) # All arguments come as strings, so need to ...

# Error messages should not go to standard output, if possible. print('ERROR: We have no cheese at all.', file=sys.stderr) try: f = open('nonexistent-file.xyz', 'rb') except OSError as e: print(e, file=sys.stderr)

def main(): if len(sys.argv) != 4 or '--help' in sys.argv[1:]: print('usage: my_program <arg1> <arg2> <arg3>', file=sys.stderr) sys.exit(1) # use an exit code to signal the program was unsuccessful process_data()

$man <command> Displays the on-line manual pages for the command $clear Clears the terminal screen $pwd Returns the working directory name $echo <string> Writes the string to the standard output $printf <string> Format and print the string Example: print $PATH ...

To show the value of making generalized functions like those in the previous example (make_title, make_axes, make_buttons, etc), consider this box and whisker chart: https://bl.ocks.org/SumNeuron/262e37e2f932cf4b693f241c52a410ff While the code for making the boxes and whiskers is more intensive tha...

As with blocks, items need models too. { "parent": "item/generated", "textures": { "layer0": "example:items/basic" } } That's pretty much all that's needed for it to work once the item is registered. The only important th...

You must have 3.2 to be able to upgrade to 3.4. This example assumes you are using apt. sudo service mongod stop sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 0C49F3730359A14518585931BC711F9BA15703C6 echo "deb [ arch=amd64,arm64 ] http://repo.mongodb.org/apt/ubuntu xeni...

Some programming languages have its own Regex peculiarities, for example, the $+ term (in C#, Perl, VB etc.) which replaces the matched text to the last group captured. Example: using System; using System.Text.RegularExpressions; public class Example { public static void Main() { ...

You first must create a "Game" object in Phaser. var game = new Phaser.Game(800, 600, Phaser.AUTO, 'phaser-example', { preload: preload, create: create }); In the preload callback function load the image. function preload() { game.load.image('thing', 'assets/thing-image.png'); ...