Deck 7: Working With Regular Expressions

Question 1

The \D character is used in a regular expression to look for a match with any numeric character.

Answer 1

False

Question 2

Regular expressions are not limited to data validation. Regular expressions can also be used to search for data within strings and to perform string substitutions.

Answer 2

True

Question 3

Using regular expressions, you can perform detailed analysis of user input to determine if it meets specific criteria.

Answer 3

True

Question 4

In regular expressions, every character inside a pattern is taken literally, with the exception of metacharacters, which are assigned a special meaning.

Question 5

The \s character is used in a regular expression to set up a match based on white space.

Question 6

The . character is used in a regular expression to look for a match at the beginning of a line.

Question 7

The operator is the "equals to" operator in a regular expression.

Question 8

While you can certainly create scripts based on the assumption that the data received will always be valid, you would do so at your own peril. In most cases, you will want to build data validation logic into your own scripts, rejecting any data that is not the proper format.

Question 9

A metacharacter is a character that alters the way a pattern match occurs.

Question 10

You can validate data using regular expressions. However, to truly create powerful validation routines, you should instead rely on conditional logic and methods belonging to Ruby classes.

Question 11

By default, regular expression matches are case sensitive, although you can override this behavior.

Question 12

Regular expressions facilitate text substitution operations. However, regular expressions are not able to accommodate differences in case.

Question 13

The most basic type of regular expression is one that matches up against a specific pattern or a set of characters. This type of pattern can be set up using the {} match operator.

Question 14

The result of the following example evaluates as true. if "Welcome to New York Harbor, USA." =~ /USA/ then puts "Welcome to America!" end

Question 15

The ^ character is used in a regular expression to look for a match at the end of a line.

Question 16

Using regular expressions, you can pick apart and process the contents of data regardless of its source, including text files and databases.

Question 17

The =~ operator is the "not equals to" operator in a regular expression.

Question 18

By default, if a character included in a regular expression pattern matches a character in the source string, true is returned.

Question 19

The \A character is used in a regular expression to look for a match at the beginning of a string.

Question 20

You can set up a regular expression pattern to look for possible matches using the | character to separate each possible match.

Question 21

You can disable case-sensitivity using the optional /c modifier as demonstrated here: /USA/c

Question 22

Data processed by computer scripts can come from many different sources, including ____.

A) Databases
B) Files
C) User Input
D) All of the above

Question 23

Which of the following regular expression metacharacters looks for a match at the end of a string?

A) \A
B) \Z
C) \w
D) \d

Question 24

Which of the following operators should be used in a regular expression to determine equality?

A) !~
B) =
C) +
D) None of the above

Question 25

Using regular expressions you can define patterns that ____.

A) Perform search and replace operations on strings
B) Keep counts of instances of patterns
C) Extract a substring from a larger string
D) All of the above

Question 26

Which of the following regular expression metacharacters matches any white space?

A) \W
B) \w
C) \S
D) \s

Question 27

Which of the following is true about regular expressions?

A) In most cases, regular expression patterns are processed from right to left.
B) Matches occur when patterns are found anywhere within a source string.
C) By default, matches are case insensitive.
D) Every character inside a pattern is taken literally, including metacharacters.

Question 28

The * metacharacter modifier is used to set up pattern matches of zero or more instances of the preceding character.

Question 29

Which of the following regular expression metacharacters matches any numeric character?

A) \d
B) \D
C) \s
D) \S

Question 30

The + metacharacter modifier is used to set up pattern matches of one or more instances of the preceding character.

Question 31

Which of the following regular expression metacharacters looks for a match at the end of a line?

A) .
B) $
C) \W
D) \w

Question 32

You can replace all instances of a search pattern using the String class's gsub method.

Question 33

The $ character is used in a regular expression to set up a match with any character.

Question 34

Which of the following regular expression metacharacters looks for a match at the beginning of a line?

A) .
B) ^
C) $
D) \w

Question 35

Which of the following regular expression metacharacters matches any non-alphabetic, non-numeric, or non-underscore character?

A) \S
B) \D
C) \W
D) \Z

Question 36

A ____ is a character that alters the way a pattern match occurs.

A) Character class
B) Pattern class
C) Metacharacter
D) Metaword

Question 37

Which of the following regular expression metacharacters matches any one character?

A) .
B) ^
C) $
D) \w

Question 38

A regular expression is ____.

A) A pattern used to identify matching character data
B) A mechanism that facilitates the collection of input
C) A special type of variable, array, or hash that facilitates pattern matching and string substitution
D) None of the above

Question 39

Which of the following statements is true in regard to the following example? if "Welcome the USA!." =~ /USA|America/ then puts "We have a match!" end

A) A pattern search has been set up to search the source string for either the words USA or America. A match occurs if either string is found.
B) A pattern search has been set up to search the source string for both the words USA and America. A match occurs only if both strings are found.
C) A case-insensitive search has been set up that searches the source string for either the words USA or America. A match occurs is either string is found.
D) None of the above.

Question 40

Which of the following regular expression metacharacters matches any non-numeric character?

A) \d
B) \D
C) \s
D) \S

Question 41

Which of the character classes can be used to match a number between 0 and 9?

A) /[numeric]/
B) /[a - x , 0 - 9]/
C) /[0-9]/
D) All of the above

Question 42

Character classes are used to search for a range of characters and are defined by placing a list of characters within ____ characters.

A) { }
B) ( )
C) # #
D) [ ]

Question 43

Which of the character classes can be used to match any lowercase letter?

A) /[abcdefghijklmnopqrstuvwxyz]/
B) /[ABCDEFGHIJKLMNOPQRSTUVWXYZ]/
C) /[A - Z]/
D) /abcdefghijklmnopqrstuvwxyz/

Question 44

Which of the following String methods can be used to substitute the first instance of a search pattern within a string?

A) sub
B) gsub
C) rsub
D) None of the above

Question 45

By default, regular expressions perform case sensitive searches. You can override this behavior sing the ____ modifier?

A) a
B) e
C) i
D) o

Question 46

Which of the following String methods can be used to replace all instances of a search pattern within a string?

A) sub
B) gsub
C) rsub
D) None of the above

Question 47

The ____ metacharacter modifier is used to search a string for zero or more instances of a character.

A) @
B) $
C) ?
D) *

Question 48

The ____ metacharacter modifier is used to search a string for one or zero instances of a character in the preceding characters.

A) @
B) $
C) ?
D) *

Question 49

The ____ metacharacter modifier is used to search a string for one or more instances of a character.

A) +
B) =
C) *
D) ?

Question 50

Which of the following character classes can be used to match a complete list of vowels?

A) /aeiou/
B) /uoiea/
C) /a - o/
D) None of the above