Strings

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?

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

A log analysis script needs to extract all IP addresses from a string. The IPs are in dotted-decimal format. Which regex pattern will correctly extract them?

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

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?

Given the string s = 'Hello World!', which expression returns a list of characters?

Which of the following is the correct way to format a string with variables?

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

Which of the following methods can be used to check if a string starts with a vowel?

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

Which TWO statements are true regarding strings in Python?

Which THREE are valid escape sequences in Python strings?

Which THREE methods return a boolean value?

What is the output?

What is the length of string s?

What is the value of matches?

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?

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?

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

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?

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

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?

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

Which TWO of the following methods return a boolean value?

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

Which TWO of the following are immutable in Python?

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

Refer to the exhibit. What is the output?

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?

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

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?

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?

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

What is the output of the code?

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?

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

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

Drag and drop the steps to install a third-party package using pip in Python into the correct order.

Match each exception to its cause.

Match each string method to its purpose.

Match each variable scope to its description.

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

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

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

A function receives a string and needs to return a new string with all vowels removed. Which code snippet accomplishes this efficiently?

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

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

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

Which of the following expressions raises a ValueError?

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

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

Which THREE of the following are true about Python strings?

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

Refer to the exhibit. What type of value is printed?

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

Refer to the exhibit. What is the output?

A developer needs to extract the domain name (e.g., 'example.com') from an email address stored in the variable 'email'. The code currently uses `email.split('@')[1]`, which returns the domain part. However, it fails for addresses containing an '@' character in the local part (e.g., 'user@name@domain.com'). Which approach correctly extracts the domain assuming the email is valid?

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

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 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 developer encounters an error: `ValueError: Unknown format code 's' for object of type 'int'` when running `print("{0:s}".format(42))`. What is the problem and how should it be fixed?

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?

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

Given `s = 'Python'`, what is the result of `s[-4::-1]`?

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 escape sequences are valid in a Python string and represent a single character? (Select exactly three.)

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

What is the output of the above code?

What is the cause of the error?

What is the output of the code?

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

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

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

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?

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

Which of the following demonstrates that strings are immutable?

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?

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

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

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

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

Which TWO of the following expressions yield the substring 'Py' from the string s = 'Python'?

Refer to the exhibit. What is the output?

Refer to the exhibit. What is printed?

Refer to the exhibit. What is the likely outcome of running this code?

A developer wrote a script that processes user input. The script expects a string containing a list of comma-separated values. The user enters "apple, banana, cherry, date". The script uses split() to separate the items. Which code correctly extracts the second item without leading/trailing spaces?

In a data processing pipeline, a string variable 'text' contains the value "Hello\nWorld\r\n". The developer needs to count the number of lines in the text. Which expression returns the correct line count (treating \n and \r\n as line terminators)?

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

A function is supposed to return True if a string contains only digits, and False otherwise. Which implementation uses a Python string method correctly?

Given: s = "Python". Which expression raises an IndexError?

Which of the following is a valid way to create an empty string in Python?

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

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

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

Which TWO of the following are valid string methods in Python? (Choose two.)

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

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

What is the output?

What is the output?

What is the output?

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

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

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

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?

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

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

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?

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

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

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

A developer is writing a function that validates a user input string to ensure it contains only ASCII digits (0-9) for a numeric ID field. Which method should be used to check the string?

A developer gets the following error while running a Python script: 'TypeError: not all arguments converted during string formatting'. The relevant code is: print('Progress: %d%%' % (percent)). The variable 'percent' is an integer. What is the most likely cause and fix?

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

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

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?

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?

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

What will the above code output?

What is the output of the code in the exhibit?

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

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

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

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 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?

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?

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

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

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

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

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]?

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

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

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

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

Refer to the exhibit. What is the output?

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

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

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

Which expression returns the last character of string s?

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

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

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

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?

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

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

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

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

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

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?

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 DevOps engineer is writing a Python script to parse a configuration file. The file contains lines like: 'PARAMETER = value'. The engineer needs to extract the value part after the '=' sign, but there may be multiple equals signs in the value (e.g., 'DATABASE = mysql://user:pass@host/db'). The engineer initially uses line.split('=')[1] but this fails if there are extra equals. Which of the following approaches correctly extracts everything after the first '=' sign?

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?

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?

A function processes a Unicode string that may contain combining characters (e.g., 'é' as 'e' plus combining acute accent). The function must return the number of visible grapheme clusters (user-perceived characters). Which of the following is the most reliable built-in approach?

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

Which THREE of the following are immutable types in Python?

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

A junior developer is building a script to convert user-provided headlines into URL slugs. The slug should contain only lowercase alphanumeric characters and single hyphens between words, with no leading or trailing hyphens. For example, 'Hello World! How are you?' should become 'hello-world-how-are-you'. The current code is: slug = input_string.lower().replace(' ', '-').replace('!', '').replace('?', ''). However, this produces multiple hyphens when there are multiple spaces, and trailing hyphens if the string ends with punctuation. The developer needs to modify the code to handle these issues reliably. Which of the following approaches is the most robust and efficient?

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?

A developer receives a string that looks like a JSON object but uses single quotes instead of double quotes and has unquoted keys. For example: "{'name': 'John', 'age': 30}". They need to convert this into a Python dictionary. They are allowed to use any standard library module. Which approach is the simplest and safest?

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 is building a template system where placeholders like {name} and {age} appear in large text documents. They have a dictionary 'data' with the replacement values. Currently, they use a loop that calls str.replace() for each placeholder, e.g., for key, value in data.items(): text = text.replace('{' + key + '}', str(value)). This works, but performance is poor on large texts with many placeholders. The developer wants to use a more efficient method from the Python standard library. Which of the following is the best alternative?

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?

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?

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?

A developer has a string that contains literal escape sequences like '\\n' and '\\t' (i.e., a backslash followed by 'n' or 't') and needs to convert them into actual control characters (newline, tab). The string comes from a configuration file that was written with double backslashes to represent single backslashes in the original configuration. The developer wants to use standard Python functionality. For example, the string "hello\\nworld" should become "hello\nworld" (a string with a real newline). Which of the following is the simplest and most reliable method?

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.)

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 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?

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

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

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?