**Prerequisite: **Lists and Tuples

**1) What is the output of the following program?**

## PYTHON

`List` `=` `[` `True` `, ` `50` `, ` `10` `]` `List` `.insert(` `2` `, ` `5` `) ` `print` `(` `List` `, ` `"Sum is: "` `, ` `sum` `(` `List` `)) ` |

a) [True, 50, 10, 5] Sum is: 66

b) [True, 50, 5, 10] Sum is: 65

c) TypeError: unsupported operand type(s) for +: ‘int’ and ‘str’

d) [True, 50, 5, 10] Sum is: 66

**Ans. (d)** **Explanation: **The List is initially has 3 elements. The insert() adds element 5 at index 2, moving element 10 at index 3 and the List becomes [True, 50, 5, 10]. Boolean has an integer value of 1, thus sum becomes 1 + 50 + 5 + 10 = 66.

**2) What is the output of the following program?**

## PYTHON

`T ` `=` `(` `1` `, ` `2` `, ` `3` `, ` `4` `, ` `5` `, ` `6` `, ` `7` `, ` `8` `)` `print` `(T[T.index(` `5` `)], end ` `=` `" "` `)` `print` `(T[T[T[` `6` `]` `-` `3` `]` `-` `6` `])` |

a) 4 0

b) 5 8

c) 5 IndexError

d) 4 1

**Ans. (b)** **Explanation: **The inbuilt function index() returns the index of the element. T.index(5) = 4 and T[4] = 5. The other print statement has indexing of tuples, similar to that of Lists. T[6] = 7, T[6]-3 = 4, T[T[6]-3] = 5, T[T[6]-3]-6 = -1 and T[T[T[6]-3]-6], i.e. T[-1] = 8.

**3) What is the output of the following program?**

## PYTHON

`L ` `=` `[` `1` `, ` `3` `, ` `5` `, ` `7` `, ` `9` `]` `print` `(L.pop(` `-` `3` `), end ` `=` `' '` `)` `print` `(L.remove(L[` `0` `]), end ` `=` `' '` `)` `print` `(L)` |

a) 5 None [3, 7, 9]

b) 5 1 [3, 7, 9]

c) 5 1 [3, 7, 9]

d) 5 None [1, 3, 7, 9]

**Ans. (a)** **Explanation: **pop() will delete and return the element whose index was passed as parameter. L.pop(-3) will delete 5 and return 5, which is printed by print(). remove() does return any value, it’s a void function. L[0] = 1, L.remove(1) will delete 1 from the list and the list remains to be [3, 7, 9].

**4) What is the output of the following program?**

## PYTHON

`def` `REVERSE(L):` ` ` `L.reverse()` ` ` `return` `(L)` `def` `YKNJS(L):` ` ` `List` `=` `[]` ` ` `List` `.extend(REVERSE(L))` ` ` `print` `(` `List` `)` `L ` `=` `[` `1` `, ` `3.1` `, ` `5.31` `, ` `7.531` `]` `YKNJS(L)` |

a) [1, 3.1, 5.31, 7.531]

b) [7.531, 5.31, 3.1, 1]

c) IndexError

d) AttributeError: ‘NoneType’ object has no attribute ‘REVERSE’

**Ans. (b)** **Explanation: **REVERSE() reverses the list and returns it. YKNJS() adds reverse of a list L to the empty list List. L = [1, 3.1, 5.31, 7.531], gets reversed and becomes [7.531, 5.31, 3.1, 1].

**5) What is the output of the following program?**

## PYTHON

`from` `math ` `import` `sqrt` `L1 ` `=` `[x` `*` `*` `2` `for` `x ` `in` `range` `(` `10` `)].pop()` `L1 ` `+` `=` `19` `print` `(sqrt(L1), end ` `=` `" "` `)` `L1 ` `=` `[x` `*` `*` `2` `for` `x ` `in` `reversed` `(` `range` `(` `10` `))].pop()` `L1 ` `+` `=` `16` `print` `(` `int` `(sqrt(L1)))` |

a) 10.0 4.0

b) 4.3588 4

c) 10 .0 4

d) 10.0 0

**Ans. (c)** **Explanation:** The first list compression will create list as [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] and pop() will return 81. 81 + 19 = 100, whose square root is 10.0 and similarly in 2nd case pop() will return 0 due to the reversed range and integer value of square root of 16 is 4.

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