Tutorial by Examples: nd

Profiling string concatanation: In [1]: import string In [2]: %%timeit s=""; long_list=list(string.ascii_letters)*50 ....: for substring in long_list: ....: s+=substring ....: 1000 loops, best of 3: 570 us per loop In [3]: %%timeit long_list=list(string.ascii_letters)*50...

Profiling concatanation of numbers python -m timeit "'-'.join(str(n) for n in range(100))" 10000 loops, best of 3: 29.2 usec per loop python -m timeit "'-'.join(map(str,range(100)))" 100000 loops, best of 3: 19.4 usec per loop

The source code with @profile directive before the function we want to profile: import requests @profile def slow_func(): s = requests.session() html=s.get("https://en.wikipedia.org/").text sum([pow(ord(x),3.1) for x in list(html)]) for i in range(50): s...

This code is to add and remove a value from a flagged enum-instance: [Flags] public enum MyEnum { Flag1 = 1 << 0, Flag2 = 1 << 1, Flag3 = 1 << 2 } var value = MyEnum.Flag1; // set additional value value |= MyEnum.Flag2; //value is now Flag1, Flag2 value...

C++14 Those following string user literals are declared in the namespace std::literals::string_literals, where both literals and string_literals are inline namespaces. Access to these operators can be gained with using namespace std::literals, using namespace std::string_literals, and using namespa...

See below for a simple example of how to use a BackgroundWorker object to perform time-intensive operations in a background thread. You need to: Define a worker method that does the time-intensive work and call it from an event handler for the DoWork event of a BackgroundWorker. Start the execu...

C++14 Those following complex user literals are declared in the namespace std::literals::complex_literals, where both literals and complex_literals are inline namespaces. Access to these operators can be gained with using namespace std::literals, using namespace std::complex_literals, and using nam...

All actions performed in a timer are handled in the "Tick" event. public partial class Form1 : Form { Timer myTimer = new Timer(); public Form1() { InitializeComponent(); myTimer.Tick += myTimer_Tick; //assign the event handler named "myT...

Parse error: syntax error, unexpected end of file in C:\xampp\htdocs\stack\index.php on line 4 If you get an error like this (or sometimes unexpected $end, depending on PHP version), you will need to make sure that you've matched up all inverted commas, all parentheses, all curly braces, all brac...

This will only install PHP. If you wish to serve a PHP file to the web you will also need to install a web-server such as Apache, Nginx, or use PHP's built in web-server (php version 5.4+). If you are in a Ubuntu version below 16.04 and want to use PHP 7 anyway, you can add Ondrej's PPA repo...

In Ruby, a string is just a sequence of bytes along with the name of an encoding (such as UTF-8, US-ASCII, ASCII-8BIT) that specifies how you might interpret those bytes as characters. Ruby strings can be used to hold text (basically a sequence of characters), in which case the UTF-8 encoding is us...

Sometimes we want to prepare a context for each test to be run under. The setUp method is run prior to each test in the class. tearDown is run at the end of every test. These methods are optional. Remember that TestCases are often used in cooperative multiple inheritance so you should be careful to...

Given the following DataFrame: In [11]: df = pd.DataFrame(np.random.randn(6, 3), columns=['A', 'B', 'C']) In [12]: df.set_index(['A', 'B'], inplace=True) In [13]: df Out[13]: C A B 0.902764 -0.259656 -1.864541 -0.695893 0.308893 0...

Given the following DataFrame: In [11]: df = pd.DataFrame({'a':[1,1,1,2,2,3],'b':[4,4,5,5,6,7,],'c':[10,11,12,13,14,15]}) In [12]: df.set_index(['a','b'], inplace=True) In [13]: df Out[13]: c a b 1 4 10 4 11 5 12 2 5 13 6 14 3 7 15 You can iterate by any lev...

This example shows how to use column data to set a MultiIndex in a pandas.DataFrame. In [1]: df = pd.DataFrame([['one', 'A', 100], ['two', 'A', 101], ['three', 'A', 102], ...: ['one', 'B', 103], ['two', 'B', 104], ['three', 'B', 105]], ...: columns=['c1'...

public class LoginActivity extends BaseAppCompatActivity { @BindView(R.id.tIETLoginEmail) EditText mEditEmail; @BindView(R.id.tIETLoginPassword) EditText mEditPassword; @Override protected void onResume() { super.onResume(); FirebaseUser firebaseUs...

public class ForgotPasswordActivity extends AppCompatActivity { @BindView(R.id.tIETForgotPasswordEmail) EditText mEditEmail; private FirebaseAuth mFirebaseAuth; private FirebaseAuth.AuthStateListener mAuthStateListener; @Override protected void onCreate(Bundle saved...

So you want to deploy your app to multiple sites? and your project has too many dependencies to install them one-by-one? Npm has a solution just issue the following command: npm init In the project's root folder then follow the instructions on screen (type in the desired value then press enter) ...

In many languages, new instances of a class are created using a special new keyword. In Ruby, new is also used to create instances of a class, but it isn't a keyword; instead, it's a static/class method, no different from any other static/class method. The definition is roughly this: class MyClass ...

This example sorts elements in ascending order of a key using a map. You can use any type, including class, instead of std::string, in the example below. #include <iostream> #include <utility> #include <map> int main() { std::map<double, std::string> sorted_map; ...