Tutorial by Topics: ons

ConstraintLayout is a ViewGroup which allows you to position and size widgets in a flexible way. It is compatible with Android 2.3 (API level 9) and higher. It allows you to create large and complex layouts with a flat view hierarchy. It is similar to RelativeLayout in that all views are laid out a...

A useful way to think about Mongo collections is in terms of Who, What, When, Where, Why, and How. Mongo has the following optimizations for different types of data: Where - GeoJSON When - ObjectID timestamps Who - Meteor Account Strings How - JSON for decision trees Which leaves the default...

/* all versions */ for ([expression]; [expression]; [expression]) one_statement for ([expression]; [expression]; [expression]) { zero or several statements } while (expression) one_statement while (expression) { zero or several statements } do one_statement while (expression); do { one o...

regexp ?switches? exp string ?matchVar? ?subMatchVar subMatchVar ...? regsub ?switches? exp string subSpec ?varName? This topic is not intended to discuss regular expressions themselves. There are many resources on the internet explaining regular expressions and tools to help build regul...

This section provides an overview of what responsive-design is, and why a developer might want to use it. It should also mention any large subjects within responsive-design, and link out to the related topics. Since the Documentation for responsive-design is new, you may need to create initial v...

A list comprehension is a syntactical tool for creating lists in a natural and concise way, as illustrated in the following code to make a list of squares of the numbers 1 to 10: [i ** 2 for i in range(1,11)] The dummy i from an existing list range is used to make a new element pattern. It is used...

SELECT column_name(s) FROM table1 UNION SELECT column_name(s) FROM table2; SELECT column_name(s) FROM table1 UNION ALL SELECT column_name(s) FROM table2; SELECT column_name(s) FROM table1 WHERE col_name="XYZ" UNION ALL SELECT column_name(s) FROM table2 WHERE col_name="XYZ&qu...