# Top 10 Most Asked Python Interview Questions With Answers Part 08

`x = ['ab', 'cd']print(len(map(list, x)))`

A TypeError occurs as the map has no len().

`x = ['ab', 'cd']print(len(list(map(list, x))))`

The length of each string is 2.

`a) set([[1,2],[3,4]])b) set([1,2,2,3,4])c) set((1,2,3,4))d) {1,2,3,4}`

Sometimes, when we want to iterate over a list, a few methods come in handy.

`filter()`: Filter lets us filter in some values based on conditional logic.

`list(filter(lambda x:x>5,range(8)))`

Ans: [6, 7]

`map()`: Map applies a function to every element in an iterable.

`list(map(lambda x:x**2,range(8)))`

Ans: [0, 1, 4, 9, 16, 25, 36, 49]

`reduce()`: Reduce repeatedly reduces a sequence pair-wise until we reach a single value

`from functools import reducereduce(lambda x,y:x-y,[1,2,3,4,5])`

Ans: -13

Note: A palindrome is a word, phrase, or sequence that reads the same backward as forward, e.g., madam, saas, nun.

`def isPalindrome(string):    left_pos = 0        right_pos = len(string) – 1    while right_pos >= left_pos:        if not string[left_pos] == string[right_pos]:            return False    left_pos += 1    right_pos -= 1    return Trueprint(isPalindrome('aza'))`
`def list_sum(num_List):    if len(num_List) == 1:        return num_List    else:        return num_List + list_sum(num_List[1:])print(list_sum([2, 4, 5, 6, 7]))`

Sample Output: 24

`#import MySQLdb module as :import MySQLdb#establish a connection to the database.db = MySQLdb.connect("host"="local host", "database-user"="user-name", "password"="password","database-name"="database")#initialize the cursor variable upon the established connection:c1 = db.cursor()#retrieve the information by defining a required query string.s = "Select * from dept"#fetch the data using fetch() methods and print it.data = c1.fetch(s)#close the database connection.db.close()`
`import randomdef random_line(fname):    lines = open(fname).read().splitlines()    return random.choice(lines)    print(random_line('test.txt'))`
`def file_lengthy(fname):    with open(fname) as f:        for i, l in enumerate(f):            pass        return i + 1print("Number of lines in the file: ",file_lengthy("test.txt"))`

If it makes for an introductory language to programming, Python must mean something. These are its qualities:

• Interpreted.
• Dynamically-typed.
• Object-oriented
• Concise and simple
• Free
• Has a large community

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MERN Stack Developer | Software Engineer| Frontend & Backend Developer | Javascript, React JS, Express JS, Node JS, MongoDB, SQL, and Python MERN Stack Developer | Software Engineer| Frontend & Backend Developer | Javascript, React JS, Express JS, Node JS, MongoDB, SQL, and Python