Tutorial by Topics

This topic illustrates how to avoid adding unwanted files (or file changes) in a Git repo. There are several ways (global or local .gitignore, .git/exclude, git update-index --assume-unchanged, and git update-index --skip-tree), but keep in mind Git is managing content, which means: ignoring actually ignores a folder content (i.e. files). An empty folder would be ignored by default, since it cannot be added anyway.

The UILabel class implements a read-only text view. You can use this class to draw one or multiple lines of static text, such as those you might use to identify other parts of your user interface. The base UILabel class provides support for both simple and complex styling of the label text. You can also control over aspects of appearance, such as whether the label uses a shadow or draws with a highlight. If needed, you can customize the appearance of your text further by subclassing.

“ An optional value either contains a value or contains nil to indicate that a value is missing”

Excerpt From: Apple Inc. “The Swift Programming Language (Swift 3.1 Edition).” iBooks. https://itun.es/us/k5SW7.l

Basic optional use cases include: for a constant (let), use of an optional within a loop (if-let), safely unwrapping an optional value within a method (guard-let), and as part of switch loops (case-let), defaulting to a value if nil, using the coalesce operator (??)

Function pointers are pointers that point to functions instead of data types. They can be used to allow variability in the function that is to be called, at run-time.

Anchor tags are commonly used to link separate webpages, but they can also be used to link between different places in a single document, often within table of contents or even launch external applications. This topic explains the implementation and application of HTML anchor tags in various roles.

An operator in a programming language is a symbol that tells the compiler or interpreter to perform a specific mathematical, relational or logical operation and produce a final result.

C has many powerful operators. Many C operators are binary operators, which means they have two operands. For example, in a / b, / is a binary operator that accepts two operands (a, b). There are some unary operators which take one operand (for example: ~, ++), and only one ternary operator ? :.

JOIN is a method of combining (joining) information from two tables. The result is a stitched set of columns from both tables, defined by the join type (INNER/OUTER/CROSS and LEFT/RIGHT/FULL, explained below) and join criteria (how rows from both tables relate).

A table may be joined to itself or to any other table. If information from more than two tables needs to be accessed, multiple joins can be specified in a FROM clause.


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