Sockets — Part 2 MCQs with Explanations

R supports single-line comments, but not multiline comments.

‘#’ is used to comment a line.

An assignment operator is used to assign a value to a variable. In JavaScript, = is the assignment operator. It assigns the value on the right to the variable on the left. Options <- , -> , and == are not assignment operators. == is a comparison operator, not an assignment operator.

R and S are loosely-typed languages and it supports all of the scalar data types you would expect: string, numbers, and booleans.

Matrices are like strictly typed two dimensional arrays. You create a matrix using the matrix function, which accepts five parameters: a vector to use as the content, the number of rows to shape the content into, the number of columns to shape the content into, an optional boolean value to indicate whether the content should be shaped by row or by column (the default is FALSE for by column), and a list that contains vectors for row names and column names: matrix([content vector], nrow=[number of rows], ncol=[number of columns], byrow=[how to sort], dimnames=[vector of row names, vector of column names]).

The c() function is used to add the vectors.

Data frames are multidimensional lists that can contain multiple data types.

The data frames can be created using the data.frame() function which accepts a number of vectors as content, and then the following parameters : row.names to specify the vector to use as row identifiers, check.rows to check consistency of row data, and check.names to check for duplicates among other syntactical checks.

The plot() function will display a different type of chart depending on the arguments that you pass in to it.

The method plot() accepts a total of 9 parameters.

Bubble charts are used to represent three-dimensional data.

The method symbols() is used to create a bubble chart natively in R.

The symbols() function can be used to draw other shapes on a plot; for more information about this type ?symbols at the R console.

The method win.metafile([filename]) is used to save chart as a Window metafile.

The syntax for the method to save chart as a ps file is : postscript([filename]) .

All of the above mentioned methods are used to save charts in different modes.

The method barplot() can be used to draw a bar plot.

With the method par(), you can make the text horizontal.

The WebPageTest API accepts totally 8 parameters, namely url, location, runs, fvonly, private, block, f, k.

This parameter allows you to set a comma separated list of block options.

Setting the private flag to 1 will make sure that the test is not displayed in the public list of tests.

If you set fvonly to 1, you get results only for the first view, and do not run the repeat view test.

The file_get_contents() is a PHP’s native function used to hit the URL and read the server’s response into a variable $wpt_response:

The file_get_contents() is a PHP’s native function used to hit the URL and read the server’s response into a variable $wpt_response:

The API returned by the method file_get_contents() can be converted into an XML object using the method SimpleXMLElement().

The img element can handle mouse events in Netscape.

The Defaultstatus is the tainted property of the window object.

The environment variable NS_ENABLE_TAINT must be enabled in order to enable data tainting.