Q.(a) Given is a Python string declaration : NAME = "Learning Python is Fun" Write the output of : print(NAME[-5:-10:-1])

The core concept here is understanding how Python's built-in string method capitalize() operates. String methods in Python are powerful tools for manipulating text data, and each has a specific function. capitalize() is designed for a very particular kind of text formatting: ensuring that a string starts with an uppercase letter and all subsequent letters are lowercase.

This method is useful when you want to format text to resemble a proper sentence start, regardless of its initial casing. It doesn't just capitalize the first letter; it also enforces lowercase for the rest of the string, which is a crucial detail often overlooked.

1. Initial String Definition:

   We begin with the string variable s assigned the value "the Truth".

   s = "the Truth"

2. Understanding s.capitalize():

   The capitalize() method is called on the string s. This method performs two distinct actions:

   • It converts the first character of the string to uppercase.
   • It converts all subsequent characters in the string to lowercase. It's important to remember that string methods in Python, like capitalize(), do not modify the original string s. Instead, they return a new string with the applied changes.

3. Applying the capitalize() method:

   Let's apply these rules to our string s = "the Truth":

   • The first character is 't'. According to the rule, this 't' will be converted to 'T'.
   • The remaining characters are "he Truth". According to the rule, all letters in this substring will be converted to lowercase. So, 'h' remains 'h', 'e' remains 'e', ' ' remains ' ', 'T' becomes 't', 'r' remains 'r', 'u' remains 'u', 't' remains 't', and 'h' remains 'h'. Combining these, "he Truth" becomes "he truth".

4. Constructing the Resulting String: …

The key here is understanding what partition() does in Python — and what it returns. Many students confuse it with split() or forget that it returns a tuple, not a list.

partition() is a string method that searches for a given separator in the string. When it finds the first occurrence, it cuts the string into three pieces: the part before the separator, the separator itself, and the part after. If the separator isn't found, it returns the original string followed by two empty strings. The result is always a tuple of three strings.

Let's trace through the code:

1. The string s is 'War and Peace by Leo Tolstoy'. The separator we're looking for is "by".

2. Python scans the string from left to right. The first occurrence of "by" appears after 'War and Peace ' — note the space before "by" is part of the first segment, not the separator. The separator "by" itself is exactly those two characters.

3. Everything before "by" is 'War and Peace ' (including the trailing space). The separator itself is 'by'. Everything after "by" is ' Leo Tolstoy' (starting with a space).

4. partition() packages these three strings into a tuple: ('War and Peace ', 'by', ' Leo Tolstoy'). …

Concept — Python string slicing with a negative step

Python's slice syntax is [start:stop:step]:

• start — the index where the slice begins.
• stop — the index where it ends; the character at stop is not included.
• step — the jump between indices. A negative step walks the string from right to left, continuing while the current index is greater than stop.

A negative index counts from the end: -1 is the last character. For a string of length 13, index -1 is the same as index 12.

Step-by-step trace

The string "PythonProgram" has 13 characters:

For [-1:2:-2]: start = -1 (that is index 12), stop = 2, step = -2. We move backward from index 12, taking every second character, and stop as soon as the index is not greater than 2:

| Current index | Included? (index > 2) | Character taken | …

Why index() behaves this way

The index() method in Python strings searches for the first occurrence of a substring and returns its zero-based position. The crucial detail: if the substring is not found, index() does not return -1 or 0 — it raises a ValueError exception and halts execution.

This is different from the find() method, which returns -1 when the substring is absent. The designers of Python made index() strict: if you ask for the position of something that doesn't exist, that's an error condition worth stopping for.

Step-by-step trace

1. Initialize the string

   game = "Olympic2024" creates a string with characters at positions:

   Position	0	1	2	3	4	5	6	7	8	9	10
   Character	O	l	y	m	p	i	c	2	0	2	4

2. Search for "C"

   The method game.index("C") looks for the uppercase letter "C" in the string.

3. Case-sensitive comparison

   Python strings are case-sensitive. The string contains a lowercase "c" at position 6, but "C" (uppercase) does not appear anywhere.

4. Exception raised

   Because "C" is not found, Python raises:

When you work with strings in Python, slicing is one of the most elegant operations at your disposal. It allows you to carve out any substring you need by specifying start and end positions. The syntax [start:end] extracts characters from index start up to (but not including) index end. When you omit the start, Python assumes you mean "from the beginning," and when you omit the end, it means "to the very end."

Let's walk through the given code with the string "MISSISSIPPI", which has 11 characters total (indices 0 through 10).

The first slice is myStr[:4]. Because there's no starting index, Python begins at position 0 and goes up to (but not including) index 4. That gives us:

• Index 0: M
• Index 1: I
• Index 2: S
• Index 3: S

So myStr[:4] produces "MISS".

The second slice is myStr[-5:]. Negative indices count backward from the end of the string. In "MISSISSIPPI", index -5 refers to the fifth character from the end. Let's map it out:

• Index -5: S (the 7th character overall, at position 6)
• Index -4: I
• Index -3: P
• Index -2: P
• Index -1: I …

The concept: methods belong to types

In Python, every object has a specific type — integers, lists, strings, etc. Each type comes with its own set of methods (functions that belong to that type). For example, lists have .append(), .pop(), and .sort(). Strings have .upper(), .lower(), .split(), and so on.

The key question here is: does the string type have a .sort() method? If not, calling it will produce an AttributeError — Python's way of saying "this object doesn't know how to do that."

Step-by-step reasoning

1. What does "HELLO".sort() actually try to do?

   The expression "HELLO".sort() attempts to call a method named sort on the string object "HELLO". Python will look for a method called sort in the string class's definition.

2. Does the string class have a sort method?

   No. Strings in Python are immutable sequences of characters. They support methods like .upper(), .lower(), .find(), .replace(), and .split(), but not .sort(). The sort() method exists only on mutable sequence types like lists.

   Watch out

   A common mistake is to confuse strings with lists. Lists have .sort() because they are mutable — you can rearrange their elements in place. Strings are immutable; you cannot change their characters in place, so sorting a string directly makes no sense.

3. What happens when you run "HELLO".sort()?

   Python raises an AttributeError with a message like:

   'str' object has no attribute 'sort' …

The core concept here revolves around understanding how Python's string partition() method works. Unlike split(), which can divide a string into many parts based on a separator and returns a list, partition() has a very specific job: it always divides the string into exactly three parts and returns them as a tuple.

Here's the breakdown of what those three parts are:

1. The part of the string before the first occurrence of the separator.
2. The separator itself.
3. The part of the string after the first occurrence of the separator.

The key is "first occurrence." If the separator appears multiple times, partition() only considers the very first one it finds. If the separator is not found in the string, partition() returns a tuple containing the original string, followed by two empty strings ('', '').

Let's apply this to the given code.

1. Identify the string and the separator.

   We have the string S = "Amrit Mahotsav @ 75".

   The partition() method is called with S.partition(" "), meaning the separator we are looking for is a single space character " ".

2. Locate the first occurrence of the separator.

   In the string "Amrit Mahotsav @ 75", the first space character appears immediately after the word "Amrit".

   S = "Amrit Mahotsav @ 75"

   ^ (First space)

3. Divide the string into three parts based on the first separator.

   • Part 1 (before the separator): Everything before the first space is "Amrit".
   • Part 2 (the separator itself): The separator is " ".
   • Part 3 (after the separator): Everything after the first space is "Mahotsav @ 75".

4. Form the tuple.

   The partition() method returns these three parts as a tuple.

   So, A will be ('Amrit', ' ', 'Mahotsav @ 75'). …

Let’s walk through what happens when Python runs this code. The string S = "Amrit Mahotsav @ 75" contains three spaces — one after "Amrit", one after "Mahotsav", and one before "75". The method split(" ",2) is called with two arguments: the delimiter (a single space) and the maximum number of splits (2).

The key idea is that split with a maxsplit argument does not split the string into all possible pieces. Instead, it performs exactly that many splits, starting from the left, and then lumps everything after the last split into one final piece. So with maxsplit=2, Python will split at the first space and at the second space, but not at the third space. After the second split, whatever remains of the string — including any further spaces — becomes the third element of the resulting list.

Let’s trace it:

• First split: at the space after "Amrit". We get "Amrit" and the rest: "Mahotsav @ 75".
• Second split: at the space after "Mahotsav". We get "Mahotsav" and the remainder: "@ 75".

The remainder "@ 75" is not split further because we have already used up both allowed splits. So the final result is a list with three elements: ['Amrit', 'Mahotsav', '@ 75'].

Now look at the options:

• (a) ('Amrit', 'Mahotsav', '@', '75') — This is a tuple with four elements. Wrong on two counts: it’s a tuple, and it has four items. …

Let's break down each statement in the provided Python code to understand its function and identify any potential errors. Understanding how Python handles strings and their available methods is key here.

In Python, strings are immutable sequences of characters. This means once a string is created, its individual characters cannot be changed, nor can elements be added or removed directly using methods like append that modify sequences in place.

• Statement 1: S="Happy"

  This statement initializes a variable S and assigns it the string value "Happy". This is a perfectly valid assignment operation.

• Statement 2: print(S*2)

  Here, the * operator is used with a string (S) and an integer (2). In Python, when a string is multiplied by an integer, it results in the string being repeated that many times. So, S*2 would evaluate to "HappyHappy". The print() function then displays this resulting string. This is a valid operation and will execute without error.

• Statement 3: S+="Independence"

  This statement uses the augmented assignment operator +=. For strings, += performs string concatenation. It is equivalent to S = S + "Independence". The current value of S ("Happy") is concatenated with the string "Independence", and the new resulting string ("HappyIndependence") is then assigned back to S. This is a valid operation and will execute without error.

  Note

  After Statement 3, the variable S now holds the value "HappyIndependence".

• Statement 4: S.append("Day") …