Tutorial by Examples: g

class File(): def __init__(self, filename, mode): self.filename = filename self.mode = mode def __enter__(self): self.open_file = open(self.filename, self.mode) return self.open_file def __exit__(self, *args): self.open_file.close() ...

OnClick Listener: @OnClick(R.id.login) public void login(View view) { // Additional logic } All arguments to the listener method are optional: @OnClick(R.id.login) public void login() { // Additional logic } Specific type will be automatically casted: @OnClick(R.id.submit) publi...

Fragments have a different view lifecycle than activities. When binding a fragment in onCreateView, set the views to null in onDestroyView. Butter Knife returns an Unbinder instance when you call bind to do this for you. Call its unbind method in the appropriate lifecycle callback. An example: pub...

You need to set who you are *before* creating any commit. That will allow commits to have the right author name and email associated to them. It has nothing to do with authentication when pushing to a remote repository (e.g. when pushing to a remote repository using your GitHub, BitBucket, or Gi...

Similar to the built-in function zip(), itertools.zip_longest will continue iterating beyond the end of the shorter of two iterables. from itertools import zip_longest a = [i for i in range(5)] # Length is 5 b = ['a', 'b', 'c', 'd', 'e', 'f', 'g'] # Length is 7 for i in zip_longest(a, b): x...

Who says you cannot throw multiple exceptions in one method. If you are not used to playing around with AggregateExceptions you may be tempted to create your own data-structure to represent many things going wrong. There are of course were another data-structure that is not an exception would be mor...

You can get list of available commands by following way: >>> python manage.py help If you don't understand any command or looking for optional arguments then you can use -h argument like this >>> python manage.py command_name -h Here command_name will be your desire command...

CSV(Comma Separated Values) is a simple file format used to store tabular data, such as a spreadsheet. This is a minimal example of how to write & read data in Python. Writing data to a CSV file: import csv data = [["Ravi", "9", "550"], ["Joe", "8...

Visual Basic has Left, Right, and Mid functions that returns characters from the Left, Right, and Middle of a string. These methods does not exist in C#, but can be implemented with Substring(). They can be implemented as an extension methods like the following: public static class StringExtens...

explode and strstr are simpler methods to get substrings by separators. A string containing several parts of text that are separated by a common character can be split into parts with the explode function. $fruits = "apple,pear,grapefruit,cherry"; print_r(explode(",",$fruits))...

In the app folder find package.json and modify the following line to include the latest version, save the file and close. "react-native": "0.32.0" In terminal: $ npm install Followed by $ react-native upgrade

Pass an open file object from Python to C extension code. You can convert the file to an integer file descriptor using PyObject_AsFileDescriptor function: PyObject *fobj; int fd = PyObject_AsFileDescriptor(fobj); if (fd < 0){ return NULL; } To convert an integer file descriptor back ...

You can also pattern match on Elixir Data Structures such as Lists. Lists Matching on a list is quite simple. [head | tail] = [1,2,3,4,5] # head == 1 # tail == [2,3,4,5] This works by matching the first (or more) elements in the list to the left hand side of the | (pipe) and the rest of the ...

Python lists are 0-based i.e. the first element in the list can be accessed by the index 0 arr = ['a', 'b', 'c', 'd'] print(arr[0]) >> 'a' You can access the second element in the list by index 1, third element by index 2 and so on: print(arr[1]) >> 'b' print(arr[2]) >> '...

Open the Settings or Preferences dialog: On Windows or Linux, select File > Settings from the main menu. On Mac OSX, select Android Studio > Preferences from the main menu. Navigate to Build, Execution, Deployment > Compiler. In the text field next to Command-line Options, enter...

The most flexible ways to sort an array is with the sortedArrayUsingComparator: method. This accepts an ^NSComparisonResult(id obj1, id obj2) block. Return Value Description NSOrderedAscending obj1 comes before obj2 NSOrderedSame obj1 and obj2 have no order NSOrdere...

Keyword lists are tuples of key/value, generally used as options for a function call. [{:a, 1}, {:b, 2}] // creates a non-empty keyword list Keyword lists can have the same key repeated more than once. [{:a, 1}, {:a, 2}, {:b, 2}] [{:a, 1}, {:b, 2}, {:a, 2}] Keys and values can be any type: ...

When Intel defined the original 8086, it was a 16-bit processor with a 20-bit address bus (see below). They defined 8 general-purpose 16-bit registers - but gave them specific roles for certain instructions: AX The Accumulator register. Many opcodes either assumed this register, or were faster i...

When Intel produced the 80386, they upgraded from a 16-bit processor to a 32-bit one. 32-bit processing means two things: both the data being manipulated was 32-bit, and the memory addresses being accessed were 32-bit. To do this, but still remain compatible with their earlier processors, they intro...

The first four 16-bit registers could have their upper- and lower-half bytes accessed directly as their own registers: AH and AL are the High and Low halves of the AX register. BH and BL are the High and Low halves of the BX register. CH and CL are the High and Low halves of the CX register. D...