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 ‘S+?@S+’ match?
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