gsub() function replaces all matches of a string. gsub() can also be used for Regular Expression.
gsub(pattern, replacement, x, ignore.case = FALSE, perl = FALSE, fixed = FALSE, useBytes = FALSE)
Example: eliminate space
x <- "R Tutorial"
Additional information about gsub() function: http://www.endmemo.com/program/R/gsub.php
Here is example to delete data frame columns using R.
DF <- data.frame(
drops <- c("x","z")
DF[,!(names(DF) %in% drops)]
Since Simon first published How To Upgrade Your BlackBerry OS, there have been a ton of updates and questions from BlackBerry Cool readers, so I thought it would be good to republish with new tips and put everything on a single page.
What you’ll need
- Desktop Manager (free 200-300 MB download)
- Handheld software (free 100+ MB download)
- Time (about two hours, counting download, device backup, and installation)
Do I need to upgrade?
The quick answer? Yes. OS upgrades come with performance enhancements and sometimes new features that will make your BlackBerry experience much smoother. While we can’t recommend grabbing unofficial software, as it could bork your device, it’s worth becoming familiar with the process and trying it out for yourself. It’s a fun process that makes getting to know your BlackBerry more fun.
Before you upgrade, make sure you have the latest software. To do this, go to Options > About and the details of your device will be displayed. Take note of the device model number and the software version. Later in this tutorial, we’ll show you how to go about finding the latest OS, and comparing it to see if you’re eligible for an upgrade. But first, lets get what you need to start the process.
Java Abstract classes are used to declare common characteristics of subclasses. An abstract class cannot be instantiated. It can only be used as a superclass for other classes that extend the abstract class. Abstract classes are declared with the abstract keyword. Abstract classes are used to provide a template or design for concrete subclasses down the inheritance tree.
Like any other class, an abstract class can contain fields that describe the characteristics and methods that describe the actions that a class can perform. An abstract class can include methods that contain no implementation. These are called abstract methods. The abstract method declaration must then end with a semicolon rather than a block. If a class has any abstract methods, whether declared or inherited, the entire class must be declared abstract. Abstract methods are used to provide a template for the classes that inherit the abstract methods.
Abstract classes cannot be instantiated; they must be subclassed, and actual implementations must be provided for the abstract methods. Any implementation specified can, of course, be overridden by additional subclasses. An object must have an implementation for all of its methods. You need to create a subclass that provides an implementation for the abstract method.
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