1. Which of the following is an important parameter of read.table function?
a) file
b) header
c) sep
d) all of the mentioned
Explanation: More parameters are required for loading the data.
2. Which of the following will set the character that represents missing value?
a) na.quote
b) na.strings
c) nrows
d) all of the mentioned
Explanation: na.strings takes a character vector.
3. Point out the wrong statement.
a) data.table inherits from data.frame
b) data.table is written in Java
c) data.table is faster at subsetting and updating data
d) none of the mentioned
Explanation: data.table is written in C.
4. Which of the following package is used for reading excel data?
a) xlsx
b) xlsc
c) read.sheet
d) all of the mentioned
Explanation: read.xlsx and read.xlsx functions are part of xlsx package.
5. Which of the following can be used to view all the tables in memory?
a) tables
b) alltable
c) table
d) none of the mentioned
Explanation: The table function is a very basic, but essential, function to master while performing interactive data analyses.
6. Which of the following function programmatically extract parts of XML file?
a) XmlSApply
b) XmlApply
c) XmlSApplyData
d) All of the mentioned
Explanation: xmlSApply are simple wrappers for tapply and lappy functions.
7. Which of the following package is used for reading JSON data?
a) jsonlite
b) json
c) jsondata
d) all of the mentioned
Explanation: The jsonlite package is a JSON generator optimized for the web.
8. Extracting XML is the basis for most web scraping.
a) True
b) False
Explanation: XML is particularly used in web applications.
9. Which of the following function gives information about top level data?
a) head
b) tail
c) summary
d) none of the mentioned
Explanation: The function head is very useful for working with lists, tables, data frames and even functions.
10. Point out the correct statement.
a) head function work on string
b) tail function work on string
c) head function work on string but tail function do not
d) none of the mentioned
Explanation: Both head and tail function do not work on strings