Tutorial by Examples: f

Running output buffer before any content

ob_start(); $user_count = 0; foreach( $users as $user ) { if( $user['access'] != 7 ) { continue; } ?> <li class="users user-<?php echo $user['id']; ?>"> <a href="<?php echo $user['link']; ?>"> <?php echo $user...

PHP • Output Buffering

Using Output buffer to store contents in a file, useful for reports, invoices etc

<?php ob_start(); ?> <html> <head> <title>Example invoice</title> </head> <body> <h1>Invoice #0000</h1> <h2>Cost: &pound;15,000</h2> ... </body> </html> <?php...

PHP • Output Buffering

Ignore files that have already been committed to a Git repository

If you have already added a file to your Git repository and now want to stop tracking it (so that it won't be present in future commits), you can remove it from the index: git rm --cached <file> This will remove the file from the repository and prevent further changes from being tracked by...

Git • Ignoring Files and Folders

Basics of multithreading

Using the threading module, a new thread of execution may be started by creating a new threading.Thread and assigning it a function to execute: import threading def foo(): print "Hello threading!" my_thread = threading.Thread(target=foo) The target parameter references the fun...

Python Language • Multithreading

Defining and Assigning

A block that performs addition of two double precision numbers, assigned to variable addition: double (^addition)(double, double) = ^double(double first, double second){ return first + second; }; The block can be subsequently called like so: double result = addition(1.0, 2.0); // result =...

Objective-C Language • Blocks

Limit and Offset relationship

Considering the following users table: idusername1User12User23User34User45User5 In order to constrain the number of rows in the result set of a SELECT query, the LIMIT clause can be used together with one or two positive integers as arguments (zero included). LIMIT clause with one argument When ...

MySQL • Limit and Offset

Getting the First Page in Ruby

This Ruby example uses Mechanize, a library to automate web interactions. client_id is an OAuth client_id. game is the game directory to list. require 'mechanize' master_agent = Mechanize.new client_id = "123" game = "Minecraft" url = "https://api.twitch.tv/kraken...

twitch • Lists of Streamers by Game

Basic Formatting

Every format type is related to an HTML tag. The First Heading refers to the <h1> tag and is visualized like: Hello World and it's written underlining the text with =: Hello World =========== or by prepending # to the text: # Hello World The Second Heading refers to the <h2&gt...

Markdown • Getting started with Markdown

Implements Interface

This is an enum that is also a callable function that tests String inputs against precompiled regular expression patterns. import java.util.function.Predicate; import java.util.regex.Pattern; enum RegEx implements Predicate<String> { UPPER("[A-Z]+"), LOWER("[a-z]+&quot...

Java Language • Enums

Function call operator

You can overload the function call operator (): Overloading must be done inside of a class/struct: //R -> Return type //Types -> any different type R operator()(Type name, Type2 name2, ...) { //Do something //return something } //Use it like this (R is return type, a and b a...

C++ • Operator Overloading

Bit shift operators for I/O

The operators << and >> are commonly used as "write" and "read" operators: std::ostream overloads << to write variables to the underlying stream (example: std::cout) std::istream overloads >> to read from the underlying stream to a variable (example: s...

C++ • Operator Overloading

Sourcing a file

Sourcing a file is different from execution, in that all commands are evaluated within the context of the current bash session - this means that any variables, function, or aliases defined will persist throughout your session. Create the file you wish to source sourceme.sh #!/bin/bash export A=...

Bash • Sourcing

Convert formatted string representation of date to Date object

This method can be used to convert a formatted string representation of a date into a Date object. /** * Parses the date using the given format. * * @param formattedDate the formatted date string * @param dateFormat the date format which was used to create the string. ...

Java Language • Date Class

Searching for a file by name or extension

To find files/directories with a specific name, relative to pwd: $ find . -name "myFile.txt" ./myFile.txt To find files/directories with a specific extension, use a wildcard: $ find . -name "*.txt" ./myFile.txt ./myFile2.txt To find files/directories matching one of ma...

Bash • Find

Finding files by type

To find files, use the -type f flag $ find . -type f To find directories, use the -type d flag $ find . -type d To find block devices, use the -type b flag $ find /dev -type b To find symlinks, use the -type l flag $ find . -type l

Bash • Find

Executing commands against a found file

Sometimes we will need to run commands against a lot of files. This can be done using xargs. find . -type d -print | xargs -r chmod 770 The above command will recursively find all directories (-type d) relative to . (which is your current working directory), and execute chmod 770 on them. The -...

Bash • Find

Counting total number of documents in last 5 minutes

lscount returns a time bucketed count of matching documents in the LogStash index, according to the specified filter. A trivial use of this would be to check how many documents in total have been received in the 5 minutes, and alert if it is below a certain threshold. A Bosun alert for this might ...

Bosun • lscount

The average value of a field over time

lsstat returns various summary stats per bucket for the specified field. The field must be numeric in elastic. rStat can be one of avg, min, max, sum, sum_of_squares, variance, std_deviation. The rest of the fields behave the same as lscount, except that there is no division based on bucketDuratio...

Bosun • lsstat

"Promisifying" values

The Promise.resolve static method can be used to wrap values into promises. let resolved = Promise.resolve(2); resolved.then(value => { // immediately invoked // value === 2 }); If value is already a promise, Promise.resolve simply recasts it. let one = new Promise(resolve => ...

JavaScript • Promises

Check whether a variable is of a certain qualified type

#include <stdio.h> #define is_const_int(x) _Generic((&x), \ const int *: "a const int", \ int *: "a non-const int", \ default: "of other type") int main(void) { const int i = 1; int j = 1; double...

C Language • Generic selection