PCAP Strings Practice Test 7 — 15 Questions

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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 8

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 9

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()

Question 10

Which three of the following statements about Python strings are true? (Choose three.)

Accepted Answer

The join() method is called on the separator string.. The join() method is called on the separator string, not on the iterable. For example, ','.join(['a', 'b']) returns 'a,b'. The separator is the string that will be placed between each element of the iterable passed as an argument. This is a common point of confusion because many learners mistakenly think join() is called on the list.

Answer

The string '123.45' can be converted to integer using int('123.45').

Answer

Strings are mutable.

Question 11

Refer to the exhibit. What is the output of the code?

Accepted Answer

Pto. The code uses slicing with a step of 2 on the string 'Python', starting at index 0 and ending at index 5 (exclusive). This extracts characters at indices 0, 2, and 4, which are 'P', 't', and 'o', resulting in 'Pto'. The correct answer is A.

Answer

Pyt

Answer

Phn

Answer

Pyh

Question 12

Refer to the exhibit. What is the output?

Accepted Answer

TypeError. The code in the exhibit attempts an operation that raises a TypeError, such as using the '+' operator between a string and an integer without proper conversion. In Python, this raises a TypeError: can only concatenate str (not 'int') to str. The other options are not consistent with the expected behavior.

Answer

IndexError

Answer

No output

Answer

Hello World

Question 13

Refer to the exhibit. A Python script uses re.split with a regex pattern. What is the output?

Accepted Answer

['one', 'two', 'three']. `re.split(r'\s+', 'one   two three')` splits the string on one or more whitespace characters (`\s+`). The pattern consumes all contiguous whitespace as a single delimiter, producing a list of the three non-empty substrings: `['one', 'two', 'three']`. No trailing empty string is included because the string does not end with whitespace.

Answer

['one   two three']

Answer

['one', 'two', 'three', '']

Answer

['one', ' ', 'two', ' ', 'three']

Question 14

A developer wants to check if a string contains only alphabetic characters. Which string method should be used?

Accepted Answer

isalpha(). The `isalpha()` method returns `True` if all characters in the string are alphabetic (letters) and the string is non-empty. This directly matches the developer's requirement to check for only alphabetic characters.

Answer

isalnum()

Answer

isspace()

Answer

isdigit()

Question 15

What is the result of the expression 'Hello' * 3?

Accepted Answer

'HelloHelloHello'. In Python, the multiplication operator (*) on a string repeats the string a specified number of times. 'Hello' * 3 concatenates 'Hello' three times, producing 'HelloHelloHello'. This is a fundamental string operation defined in Python's sequence protocol.

Answer

'Hello3'

Answer

'Hello Hello Hello'

Answer

TypeError