Strings

A developer is writing a function to reverse each word in a sentence while preserving the original order of the words. For example, 'Hello World' should become 'olleH dlroW'. The current implementation is: def reverse_words(s): return ' '.join(word[::-1] for word in s.split()). This works for simple cases. However, the input may contain multiple spaces between words (e.g., 'Hello World') and tabs. The requirement is to preserve the exact whitespace between words (including tabs and multiple spaces) in the output. Which of the following modifications will achieve this while keeping the approach efficient?

Refer to the exhibit. What happens when the code is executed?

A QA engineer needs to verify that a user input string contains at least one uppercase letter, one lowercase letter, and one digit. Which regex pattern can be used with re.search() to achieve this?

Which THREE of the following are immutable types in Python?

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

A junior developer is parsing a log file where each line has comma-separated fields. However, some fields are enclosed in double quotes and contain commas inside, e.g., '2023-08-15 14:30:00,WARNING,"Disk space low, please clean up".'. They are required to parse these lines using only built-in string methods (no modules like csv or re). Which approach is the most reliable and efficient?

Drag and drop the steps to handle an exception in Python using try-except-finally into the correct order.

You are a network engineer troubleshooting a script that processes router configuration files. The script reads a configuration line from a file: 'interface GigabitEthernet0/1 ip address 192.168.1.1 255.255.255.0 no shutdown'. The script needs to extract the interface name and IP address. The current code uses string split operations but fails when the line has extra spaces or tabs. For example, when the line is 'interface GigabitEthernet0/1', the split returns ['interface', '', '', 'GigabitEthernet0/1'] and the script fails. You need to modify the script to robustly extract the interface name and IP address regardless of whitespace. Which approach should you take?

What is the cause of the error?

Consider the following code: print(type('apple,banana,cherry'.split(','))) What type of value is printed?

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?

You are a developer at a company that processes customer feedback. Each feedback entry is stored as a string containing a rating (1-5) followed by a colon and then the comment. For example: '4: Great service'. You need to extract only the comments from feedback that have a rating of 4 or 5. You have a list of feedback strings. Which code snippet correctly implements this?

What is the result of 'PyThon'.lower()?

A data pipeline processes CSV lines that may contain quoted fields with commas inside double quotes. For example: 'John, "Doe, Jr.", 35'. The team needs to split such a line correctly. Which approach is best?

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

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

Which of the following is the BEST practice for building a large string by concatenating many smaller strings in Python?

Refer to the exhibit. Which of the following fixes the error?

Which TWO statements are true regarding strings in Python?

A data analyst is cleaning a CSV file. They have a string variable containing a row of data: 'John,Doe,30,New York'. They need to extract the last name 'Doe' using string methods. The analyst writes: name = row.split(',')[1]. However, they are concerned about performance because the file contains millions of rows. They want to use a more efficient method that extracts the substring without creating a full list. Which approach should the analyst use?

A developer writes code to display a floating-point number with exactly two decimal places. Which f-string expression is correct for value = 3.14159?

A developer wants to replace all vowels in a string with their corresponding uppercase letters. They wrote: `s = 'hello world'`; `vowels = 'aeiou'`; `trans = str.maketrans(vowels, vowels.upper())`; `result = s.translate(trans)`. What is the value of `result`?

A programmer wants to check whether a string `s` is a palindrome (reads the same forwards and backwards, ignoring case and non-alphanumeric characters). Which code snippet correctly implements this?

A function receives a file path like '/home/user/docs/file.txt' and needs to return the path without the file extension, e.g., '/home/user/docs/file'. Which code reliably removes only the last dot extension, even if the directory names contain dots?

You are developing a high-performance logging module that must handle thousands of log entries per second. Each entry is built by concatenating a timestamp, level, and message. Currently, your code uses a loop that repeatedly appends to a string using the += operator. This results in high memory usage and sluggish performance because each concatenation creates a new string object. The module must run on systems with limited memory and cannot rely on external libraries. Which course of action would best resolve the performance issue while maintaining readability and standard library compliance?

Which TWO string methods are used to determine if a string begins or ends with a specified prefix or suffix? (Choose two.)

A script reads a binary file and decodes it as UTF-8. Some bytes are invalid UTF-8 sequences, causing a `UnicodeDecodeError`. The developer wants to replace invalid bytes with the replacement character U+FFFD. Which approach achieves this?

A Python script reads a file containing text with non-ASCII characters like 'é' and 'ü'. The script must encode the string as UTF-8 then decode it back. Which of the following correctly handles this without error?

A developer wants to check if a string 'example.txt' ends with '.txt'. Which expression returns True?

A team is using f-strings to format a report. They have a variable `value = 0.123456789` and want to display it with exactly 3 significant digits. They write `f"{value:.3g}"`. The output is '0.123'. They expected '0.123'. Is the output correct? If not, what change would produce '0.123'?

A network engineer processes a configuration file containing MAC addresses in the format 'aa:bb:cc:dd:ee:ff'. They need to convert each MAC address into a 6-byte bytes object for use in packet crafting. The current code is: mac_bytes = bytes([int(x, 16) for x in mac_str.split(':')]). This works correctly, but they need to process thousands of MAC addresses and want to optimize performance. They also need to handle invalid MAC addresses (e.g., non-hex characters) without crashing. Which of the following approaches is the most efficient and robust?

A developer generates a report where numbers must be right-aligned in a 10-character column using f-strings: f'{value:>10}'. However, some values may be None, causing a TypeError. Which is the most robust way to handle None values without affecting other falsy values like 0?

What does the expression 'hello world'.title() return?

Match each string method to its purpose.

What is the value of matches?

Which TWO of the following string methods return a new string with all characters converted to lowercase? (Select exactly two.)

Which THREE of the following are true about Python strings?

What is the result of 'abcdef'[::-2]?

A developer needs to replace all occurrences of 'cat' with 'dog' in a string, but only if 'cat' is a whole word (not part of 'category'). Which code achieves this?

A developer is working with a string `text = "The quick brown fox jumps over the lazy dog"`. They want to create a new string where every occurrence of the word 'the' (case-insensitive) is replaced with 'a'. However, they must not replace 'the' when it is part of another word, such as in 'then' or 'there'. Which approach correctly achieves this?

A developer wants to convert a string 'Python' to all uppercase letters. Which string method should be used?

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?

What is the output of `print('-'.join(['a', 'b', 'c']))`?

A cloud infrastructure engineer is developing a Python script to parse large configuration files from a fleet of servers. Each file can be up to 500 MB. The script reads the file line by line using a file object, strips comment lines (those starting with '#'), and accumulates only the configuration directives into a single string for further processing. The current code is: ```python result = '' with open('config.cfg') as f: for line in f: if not line.startswith('#'): result += line.strip() ``` After processing just a few hundred lines of a large file, the script becomes extremely slow and consumes an excessive amount of memory. The engineer identifies that string concatenation using `+=` is inefficient because strings are immutable, causing repeated memory reallocation. Which approach should the engineer implement to resolve the performance issue without changing the final output?

A developer is building a large string by concatenating many substrings in a loop using '+'. What is the main performance issue?

A programmer writes a function to check if a string is a palindrome (ignoring case and non-alphanumeric characters). Which implementation correctly achieves this?

Match each exception to its cause.

A developer is cleaning data from a CSV file. They have a string `record = "John,Doe,35,Engineer"` and want to replace all commas with semicolons. However, they also want to ensure that any leading or trailing whitespace in the entire string is removed before the replacement. Which expression produces the desired result?

A developer wants to remove all leading and trailing whitespace from a string, but preserve internal spaces. Which line of code accomplishes this?

Given s = 'Python', which THREE of the following expressions evaluate to True? (Choose three.)

A beginner programmer writes: name = "Alice"; print("Hello " + name). Which string method alternative is more efficient and recommended for Python 3?

A developer needs to parse a log file where each line contains a timestamp followed by a message. The timestamp format is 'YYYY-MM-DD HH:MM:SS'. Which string method is most appropriate to split the timestamp from the message?

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?

A developer needs to combine a list of 10,000 strings into a single string. Which approach is most efficient in terms of memory and performance?

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

Which TWO of the following methods return a boolean value?

A data entry application reads a CSV file where each line contains fields separated by commas. However, some fields are enclosed in double quotes and contain commas inside, e.g., 'John,"Doe, Jr.",30'. The developer currently uses line.split(',') to parse each line, which incorrectly splits the quoted field. The developer wants a solution using only the Python standard library (no third-party packages). Which of the following is the best approach?

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

A programmer is writing a script to generate SQL queries safely. They need to escape single quotes in user-provided strings to prevent injection. Which approach is most robust?

Given s = 'Python', what is s[1:4]?

A developer writes a log message with variables: name = 'Alice' and age = 30. Which of the following uses an f-string correctly?

Consider the following code: name = "Alice" age = 30 print(f"{name} is {age} years old.") What is the output of the above code?

Which TWO of the following string methods return a boolean value (True or False)?

Which TWO string methods raise an exception when the searched substring is not found?

Which TWO statements about Python strings are correct? (Choose exactly 2 correct answers.)

A developer wants to check if a string 'racecar' is a palindrome by comparing it to its reverse. Which code completes the task correctly?

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

A developer is tasked with validating user input that must be a 10-digit phone number. The input may contain spaces, dashes, and parentheses. Which approach best ensures the input contains exactly 10 digits?

What is the likely outcome of running the following code? ```python with open("C:\Users\path\file.txt", "r") as f: print(f.read()) ```

You are a data analyst working with a dataset of customer reviews. Each review is stored as a string in a list. You need to count how many reviews contain the word 'excellent' (case-insensitive). However, the word might appear as 'Excellent', 'EXCELLENT', or even with punctuation like 'excellent!'. The current code uses 'excellent' in review.lower(), but this fails if 'excellent' is part of another word like 'unexcellent'. You need to ensure that only the whole word 'excellent' is counted. Which code modification will correctly count whole word occurrences?

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

What is the output of the code in the exhibit?

A junior developer is writing a script that processes user input. The script reads a line of text from the console and needs to remove any leading or trailing whitespace. The developer uses the strip() method but notices that it also removes other characters like newline. However, the requirement is to remove only spaces (not tabs or newlines). Which course of action should the developer take to remove only leading and trailing spaces?

Given the code: s = 'Python'; t = s; s = s + '3.0'. What is the value of t after these lines execute?

What is the output?

A developer needs to count the number of occurrences of the substring 'is' in the string 'This is a test. Is this a test?'. Which code correctly performs the count?

Which THREE are valid ways to create a multiline string in Python?

Refer to the exhibit. What is the output?

Which of the following expressions returns True if the string s contains only hexadecimal digits (0-9, a-f, A-F)?

A developer is formatting a log message and wants to ensure that a string variable `name` is centered within a field of width 20, padded with asterisks (`*`) on both sides. For example, if `name = "Alice"`, the result should be `*******Alice********` (7 asterisks on the left, 8 on the right). Which method call achieves this?

Given s = 'a1b2c3', which TWO of the following expressions return the string '123'?

Which TWO of the following can be used to remove leading whitespace (spaces, tabs, newlines) from a string? (Choose exactly 2 correct answers.)

A developer wants to remove leading and trailing whitespace from a string. Which method should be used?

Which of the following is the correct way to format a string to include a variable value with two decimal places in Python?

A developer needs to check if a filename starts with the prefix 'report_'. Which string method should be used?

Which TWO of the following string methods return a boolean value?

You are a developer for an e-commerce platform. The system receives product descriptions from suppliers in various formats. One supplier sends descriptions with inconsistent capitalization, extra whitespace, and occasional leading/trailing punctuation. Your task is to write a function that normalizes these descriptions: convert to lowercase, remove leading/trailing whitespace and punctuation (.,!?;:), and replace multiple spaces with a single space. The function should return the cleaned string. Which implementation correctly performs all these steps?

A programmer has a string 'apple,banana,orange' and wants to get a list ['apple', 'banana', 'orange']. Which method should be used?

A programmer has a string s = 'Python programming is fun'. They want to extract the word 'programming'. Which slicing expression achieves this?

A logging module receives a message that may contain sensitive data. To comply with data privacy, all digits in the message should be replaced with 'X' before logging. Which approach correctly achieves this?

What is the result of the expression 'aBc'.lower()?

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?

What is the output of 'hello'.count('l')?

Which of the following demonstrates that strings are immutable?

What is the result of 'Python'.find('th')?

Drag and drop the steps to debug a Python script using pdb into the correct order.

A user entered a string ' Hello, World! '. Which expression returns 'Hello, World!'?

Which THREE methods return a boolean value?

A developer is working on a logging system where dynamic values are inserted into a template string. The template is 'User %s logged in at %s'. The developer has the username and timestamp as separate variables. Which approach is most Pythonic (PEP 498) and recommended for new code?

When processing a large text file, a developer notices that using str.replace() in a loop is slow. Which alternative is most efficient for multiple replacements?

A developer writes: s = 'abc'; s[0] = 'x'. What happens?

Which THREE of the following are valid ways to create a string in Python?

Which of the following expressions returns the string 'Hello' repeated three times?

Which expression returns the last character of string s?

Which THREE of the following escape sequences are valid in a Python string and represent a single character? (Select exactly three.)

Which string method would you use to check if a string starts with a specified prefix?

What is the result of the expression '123'.zfill(5)?

A developer is building an IoT application that reads temperature data from a sensor over a TCP socket. The sensor sends data as a stream of bytes encoded in UTF-8, with each reading terminated by a newline character. The developer uses the following code to receive data: ```python import socket s = socket.socket() s.connect(('sensor.local', 5000)) data = s.recv(1024) ``` The variable `data` is a bytes object. The developer needs to convert it to a string to parse the temperature value. Which of the following lines of code should the developer use to correctly obtain the string representation of the received data, assuming the data is valid UTF-8 and may contain non-ASCII characters?

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

What will the above code output?

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

A developer is validating user input in a Python application. The string variable `input_str` is assigned the value `'Hello World'`. Which TWO of the following conditions evaluate to `True`? (Choose two.)

Consider the following code snippet: s = 'abcdefgh'; result = s[7:3:-2]; print(result). What is the output?

A web application receives a byte string b'\xc3\xa9' which represents the character 'é' in UTF-8. The developer wants to convert it to a Python string. Which operation should be used?

Which THREE of the following string methods can be used to split a string into a list of substrings? (Choose three.)

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

Which TWO of the following are valid string methods in Python?

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

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

Given the string 'Python', what is the result of 'Python'[::-1]?

Which TWO of the following expressions evaluate to `True`? (Select exactly two.)

Which string method can be used to check if a string contains only digits?

Consider the following code: result = ' '.join(['a', 'b', 'c']) print(repr(result)) What is the output?

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

A data scientist needs to count the occurrences of a substring in a long DNA sequence (e.g., 1 million bases). However, the count must include overlapping occurrences. For example, in 'AAAA', the substring 'AA' appears three times overlapping. The built-in count() method does not count overlapping matches. The scientist needs a function to count overlapping substrings efficiently without using third-party libraries. Which of the following approaches is the most efficient for this task?

Consider the following code: print('"age": 30,')

Which TWO of the following string methods return a new string without modifying the original?

What is the output of the following code? s = 'Hello'; print(s.find('l'))

Which THREE of the following expressions return the string "Python"? (Choose three.)

Which TWO of the following are immutable in Python?

Which TWO of the following string methods modify the string in place? (Note: Python strings are immutable.)

Which THREE are valid escape sequences in Python strings?

Which THREE of the following are valid string methods in Python? (Choose three.)

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

Which of the following expressions raises a ValueError?

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

Match each variable scope to its description.

A developer is building a configuration parser. They have a string `line = " key = value "` and need to remove the leading and trailing spaces, then split the line at the equals sign into a list of exactly two elements: the key and the value, with any spaces around the equals sign removed. Which expression achieves this?

Which TWO of the following operations can be performed on a string?

A developer wants to check if a string ends with a specific suffix. Which method should be used?

A developer needs to format a floating-point number 123.456789 with exactly 2 decimal places and a width of 10 characters, right-aligned. Which format specifier accomplishes this?

A developer writes a function to reverse a string: def reverse_str(s): return s[::-1]. Which of the following statements about this function is true?

A developer tries to modify a string: s = 'hello'; s[0] = 'H'. What happens when this code runs?

A developer needs to extract the file extension from a string like 'report.pdf'. Which string method is most appropriate?

Which THREE of the following are valid escape sequences in Python strings?

In a performance-critical application, you need to concatenate many strings in a loop. Which TWO approaches are most efficient?

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

Which of the following best describes the immutability of strings in Python?

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

A programmer writes a function that expects a string and returns it reversed. Which code snippet correctly reverses the string 'stressed' to 'desserts'?

Which TWO of the following are valid ways to use string formatting in Python? (Choose two.)