# Regular Expressions >> Using Python to Access Web Data

## Regular Expressions >> Using Python to Access Web Data

1. Which of the following best describes “Regular Expressions”?

• A way to calculate mathematical values paying attention to operator precedence
• The way Python handles and recovers from errors that would otherwise cause a traceback
• A small programming language unto itself
• A way to solve Algebra formulas for the unknown value

2. What will the ‘\$’ regular expression match?

• The end of a line
• A new line at the end of a line
• The beginning of a line
• A dollar sign
• An empty line

3. What would the following mean in a regular expression? [a-z0-9]

• Match anything but a lowercase letter or digit
• Match an entire line as long as it is lowercase letters or digits
• Match any text that is surrounded by square braces
• Match any number of lowercase letters followed by any number of digits
• Match a lowercase letter or a digit

4. What is the type of the return value of the re.findall() method?

• A single character
• A list of strings
• A boolean
• A string
• An integer

5. What is the “wild card” character in a regular expression (i.e., the character that matches any character)?

• *
• ?
• ^
• \$
• .
• +

6. What is the difference between the “+” and “*” character in regular expressions?

• The “+” matches at least one character and the “*” matches zero or more characters
• The “+” matches upper case characters and the “*” matches lowercase characters
• The “+” matches the beginning of a line and the “*” matches the end of a line
• The “+” matches the actual plus character and the “*” matches any character
• The “+” indicates “start of extraction” and the “*” indicates the “end of extraction”

7. What does the “[0-9]+” match in a regular expression?

• One or more digits
• Zero or more digits
• Several digits followed by a plus sign
• Any number of digits at the beginning of a line
• Any mathematical expression

8. What does the following Python sequence print out?

`x = 'From: Using the : character' y = re.findall('^F.+:', x) print(y)`
• [‘From:’]
• :
• From:
• ^F.+:
• [‘From: Using the :’]

9. What character do you add to the “+” or “*” to indicate that the match is to be done in a non-greedy manner?

• \$
• g
• ?
• ++
• **
• ^

10. Given the following line of text:

`x = 'From: Using the : character' y = re.findall('^F.+:', x) print(y)`

What would the regular expression ‘[email protected]+’ match?