PCAP Strings Practice Test 10 — 15 Questions

Question 1

Given the code above, what is printed? Note: each backslash is a single character.

Accepted Answer

23. The string "C:\Users\John\Documents" uses double backslashes to represent literal backslashes. Each double backslash `\` is a single backslash character. Counting all characters: C, :, \, U, s, e, r, s, \, J, o, h, n, \, D, o, c, u, m, e, n, t, s = 23 characters. Thus, the length is 23.

Answer

21

Answer

22

Answer

24

Question 2

Which THREE of the following string methods return a boolean value (True or False)? (Choose exactly 3 correct answers.)

Accepted Answer

isspace(). The `isspace()` method returns `True` if all characters in the string are whitespace characters (e.g., space, tab, newline) and the string is non-empty; otherwise, it returns `False`. This is a boolean-returning method that checks a specific character property, making option A correct.

Answer

replace()

Answer

find()

Question 3

A developer writes: print('{:,}'.format(1234567)). What is the output?

Accepted Answer

1,234,567. The correct output is '1,234,567' because the format specifier '{:,}' uses the comma as a thousands separator in Python's string formatting. When applied to the integer 1234567, it inserts commas every three digits from the right, producing the locale-independent grouping.

Answer

1234567

Answer

1.234.567

Answer

1 234 567

Question 4

A developer uses the .index() method on a string to find the position of a substring. If the substring is not found, what exception is raised?

Accepted Answer

ValueError. The `.index()` method on a string raises a `ValueError` when the specified substring is not found. This is because `ValueError` is the standard Python exception for cases where a function receives an argument with the correct type but an inappropriate value, such as a substring that does not exist in the target string.

Answer

KeyError

Answer

IndexError

Answer

TypeError

Question 5

A developer wants to create a string that contains the current year and month in the format 'YYYY-MM'. The year and month are stored in integer variables year and month. Which expression would produce the desired result?

Accepted Answer

f"{year}-{month:02d}". Uses an f-string with the format specifier `:02d` to zero-pad the month to two digits, ensuring that months 1-9 appear as '01', '02', etc. This produces the exact 'YYYY-MM' format from integer variables without manual conversion or padding.

Answer

year + '-' + month

Answer

str(year) + '-' + str(month)

Answer

'%s-%s' % (year, month)

Question 6

A log processing script receives a multiline string log. The script needs to check if the string ends with the substring 'ERROR'. Which method should be used?

Accepted Answer

log.endswith('ERROR'). The `endswith()` method is specifically designed to check if a string ends with a given substring. It returns `True` if the string ends with 'ERROR', making it the most direct and readable solution for this requirement.

Answer

log.find('ERROR') != -1

Answer

log.rfind('ERROR') == len(log)-5

Answer

'ERROR' in log

Question 7

A programmer needs to replace every occurrence of 'cat' with 'dog' in a string s, but only if 'cat' is not preceded by 'big'. Which regex substitution would achieve this?

Accepted Answer

re.sub(r'(?<!big)cat', 'dog', s). Uses a negative lookbehind assertion `(?<!big)` to match 'cat' only when it is NOT preceded by 'big'. This ensures that 'bigcat' remains unchanged while standalone 'cat' is replaced with 'dog'. The `re.sub` function then substitutes all such matches in the string.

Answer

re.sub(r'bigcat', 'dog', s)

Answer

re.sub(r'cat', 'dog', s)

Answer

re.sub(r'(?<=big)cat', 'dog', s)

Question 8

What is the result of the expression 'Hello'[1:3]?

Accepted Answer

'el'. In Python, string slicing uses the syntax `string[start:stop]`, where `start` is inclusive and `stop` is exclusive. For `'Hello'[1:3]`, the indices are: index 1 = 'e', index 2 = 'l', and index 3 is not included, so the slice returns 'el'. This is a fundamental string slicing behavior defined in Python's sequence protocol.

Answer

'lo'

Answer

'He'

Answer

'ell'

Question 9

Which method returns the lowest index where a specified substring is found, or -1 if not found?

Accepted Answer

find(). The `find()` method in Python returns the lowest index where the specified substring is found within the string, or -1 if the substring is not present. This behavior directly matches the question's requirement, making option A correct.

Answer

locate()

Answer

search()

Answer

index()

Question 10

Under CPython, what is the result of the following code? a = 'hello'; b = 'hello'; print(a is b)

Accepted Answer

True. CPython interns short strings as an optimization, meaning both variables 'a' and 'b' reference the same immutable string object in memory. The 'is' operator checks object identity, not value equality, so it returns True when both variables point to the same interned object.

Answer

False

Answer

NameError

Answer

None

Question 11

What happens when you execute the following code? s = 'hello'; s[0] = 'H'

Accepted Answer

TypeError is raised. In Python, strings are immutable, meaning their contents cannot be changed after creation. Attempting to assign a new character to an index position (e.g., `s[0] = 'H'`) raises a `TypeError`, not an `AttributeError` or `IndexError`, because the operation is a disallowed assignment on an immutable sequence type.

Answer

AttributeError is raised

Answer

String becomes 'Hello'

Answer

IndexError is raised

Question 12

A developer needs to extract the file extension from a filename like 'document.pdf'. Which expression returns 'pdf'?

Accepted Answer

filename.rsplit('.', 1)[-1]. `rsplit('.', 1)[-1]` splits the string from the right at the last occurrence of the dot, limiting to one split, and then retrieves the last element (index -1), which is the file extension. This handles filenames with multiple dots (e.g., 'archive.tar.gz') correctly, returning only the final extension.

Answer

filename.split('.')[1]

Answer

filename.split('.')[0]

Answer

filename[-3:]

Question 13

What is the result of the expression '12345'[:10]?

Accepted Answer

'12345'. In Python, slicing a string with a start index of 0 and an end index of 10 (as in '12345'[:10]) returns the entire string if the slice end exceeds the string length. Since '12345' has only 5 characters, the slice extracts all characters without padding or error, resulting in '12345'.

Answer

'12345     '

Answer

IndexError

Answer

'12345 '

Question 14

Which two of the following are valid ways to create a multiline string in Python source code? (Choose two.)

Accepted Answer

s = """Line1
Line2""". Triple-quoted strings ("""...""") in Python allow multiline content directly in source code, including explicit escape sequences like 
. The triple quotes preserve the string as a single object spanning multiple lines, making it a valid multiline string.

Answer

s = "Line1
Line2"

Answer

s = 'Line1' 'Line2'

Answer

s = 'Line1
Line2'

Question 15

Which two methods can be used to remove leading whitespace from a string? (Choose two.)

Accepted Answer

s.strip(). `s.strip()` removes both leading and trailing whitespace from the string, including spaces, tabs, and newline characters. This method is commonly used when you need to clean up a string entirely, but it does more than just leading whitespace removal.

Answer

s.split()

Answer

s.chomp()

Answer

s.rstrip()