Tutorial by Examples: g

This pattern can be used to contain a registered Pools of Singletons, each distinguished by unique ID: abstract class MultitonRegistryAbstract { /** * @var array */ protected static $instances = []; /** * @param string $id */ final protected function ...

In bash, you have to quote arguments in order to preserve white space: # bash function print_first_argument { echo "$1" } argument="has white space" print_first_argument "$argument" In Zsh, you don't need the quotes, because of different evaluation orde...

If a target matches multiple pattern rules, make will use the one whose prerequisites exist or can be built. For example: %.o: %.c $(CC) $(CFLAGS) -c $< -o $@ %.o: %.s $(AS) $(ASFLAGS) $< -o $@ Will compile foo.c to foo.o or assemble foo.s to foo.o, depending on which one of foo...

Pattern rules can have multiple targets but, unlike normal rules, the recipe is responsible for making all the targets. For example: debug/%.o release/%.o: %.c $(CC) $(CFLAGS_DEBUG) -c $< -o debug/$*.o $(CC) $(CFLAGS_RELEASE) -c $< -o release/$*.o Is a valid rule, which will buil...

To enable the ripple animation in a CardView, add the following attributes: <android.support.v7.widget.CardView ... android:clickable="true" android:foreground="?android:attr/selectableItemBackground"> ... </android.support.v7.widget.CardView>

If you want to add a UIImageView to the center of the screen with width and height of 100 pixel, you need to set center x constraint and center y constraint to the superview from the UIImageView and width, height constraint to the UIIMageView. Here is the code. There is way to do this in storyboard ...

If you need to listen for changes to the page selected you can implement the ViewPager.OnPageChangeListener listener on the ViewPager: viewPager.addOnPageChangeListener(new OnPageChangeListener() { // This method will be invoked when a new page becomes selected. Animation is not necessar...

In some cases, you would need to execute SQL query placed in string. EXEC, EXECUTE, or system procedure sp_executesql can execute any SQL query provided as string: sp_executesql N'SELECT * FROM sys.objects' -- or sp_executesql @stmt = N'SELECT * FROM sys.objects' -- or EXEC sp_executesql N'SEL...

Django's built-in User model is not always appropiate for some kinds of projects. On some sites it might make more sense to use an email address instead of a username for instance. You can override the default User model adding your customized User model to the AUTH_USER_MODEL setting, in your proj...

Your code will not work in projects where you reference the User model (and where the AUTH_USER_MODEL setting has been changed) directly. For example: if you want to create Post model for a blog with a customized User model, you should specify the custom User model like this: from django.conf impo...

jQuery accepts a wide variety of parameters as "selectors", and one of them is an HTML string. Passing an HTML string to jQuery will cause the underlying array-like structure of the jQuery object to hold the resulting constructed HTML. jQuery uses regex to determine if the string being pa...

from scipy.stats import rv_continuous import numpy class Neg_exp(rv_continuous): def _cdf(self, x, lamda): return 1-numpy.exp(-lamda*x) neg_exp = Neg_exp(name="Negative exponential", a=0) print (neg_exp.pdf(0,.5)) print (neg_exp.pdf(5,.5)) print (neg_exp.cdf(5...

There are many reasons a write operation may fail. A frequent one is because your security rules reject the operation, for example because you're not authenticated (by default a database can only be accessed by an authenticated user). You can see these security rule violations in the output of your...

SQL Server 2008 The ROW_NUMBER function can assign an incrementing number to each row in a result set. Combined with a Common Table Expression that uses a BETWEEN operator, it is possible to create 'pages' of result sets. For example: page one containing results 1-10, page two containing results 11...

SQL Server 2012 The OFFSET FETCH clause implements pagination in a more concise manner. With it, it's possible to skip N1 rows (specified in OFFSET) and return the next N2 rows (specified in FETCH): SELECT * FROM sys.objects ORDER BY object_id OFFSET 40 ROWS FETCH NEXT 10 ROWS ONLY The ORDER...

In earlier versions of SQL Server, developers had to use double sorting combined with the TOP keyword to return rows in a page: SELECT TOP 10 * FROM ( SELECT TOP 50 object_id, name, type, create_date FROM sys.objects ORDER BY name ASC ) AS data ...

// It's possible to unpack tuples to assign their inner values to variables let tup = (0, 1, 2); // Unpack the tuple into variables a, b, and c let (a, b, c) = tup; assert_eq!(a, 0); assert_eq!(b, 1); // This works for nested data structures and other complex data types let complex = ((1,...

Writing a gzipped file To write a gzipped file, use the module IO::Compress::Gzip and create a filehandle by creating a new instance of IO::Compress::Gzip for the desired output file: use strict; use warnings; use open qw( :encoding(UTF-8) :std ); # Make UTF-8 default encoding use IO::Compres...

Generating the minimum number of operations to transform one tree into another have a complexity in the order of O(n^3) where n is the number of nodes in the tree. React relies on two assumptions to solve this problem in a linear time - O(n) Two components of the same class will generate sim...

ContactManager contactManager = Factory.CreateObject("tracking/contactManager", true) as ContactManager; Contact contact = contactManager.LoadContactReadOnly(userName); return contact;