python - Interview Questions and Answers

11) What is the difference between remove() function and del statement?

You can use the remove() function to delete a specific object in the list.

If you want to delete an object at a specific location (index) in the list, you can either use del or pop.

Note: You don't need to import any extra module to use these functions for removing an element from the list.

We cannot use these methods with a tuple because the tuple is different from the list.

12)

What is swapcase() function in the Python?

It is a string's function which converts all uppercase characters into lowercase and vice versa. It is used to alter the existing case of the string. This method creates a copy of the string which contains all the characters in the swap case. If the string is in lowercase, it generates a small case string and vice versa. It automatically ignores all the non-alphabetic characters. See an example below.

string = "IT IS IN LOWERCASE." print(string.swapcase()) string = "it is in uppercase." print(string.swapcase()) 

  it is in lowercase.   IT IS IN UPPERCASE.

13) How to remove whitespaces from a string in Python?

To remove the whitespaces and trailing spaces from the string, Python providies strip([str]) built-in function. This function returns a copy of the string after removing whitespaces if present. Otherwise returns original string.

  string = "  javatpoint "  string2 = "    javatpoint        "  string3 = "       javatpoint"  print(string)  print(string2)  print(string3)  print("After stripping all have placed in a sequence:")  print(string.strip())  print(string2.strip())  print(string3.strip())  

  javatpoint       javatpoint                 javatpoint

After stripping all have placed in a sequence:

javatpoint

14) How to remove leading whitespaces from a string in the Python?

To remove leading characters from a string, we can use lstrip() function. It is Python string function which takes an optional char type parameter. If a parameter is provided, it removes the character. Otherwise, it removes all the leading spaces from the string.

  string = "  javatpoint "   string2 = "    javatpoint        "  print(string)  print(string2)  print("After stripping all leading whitespaces:")  print(string.lstrip())  print(string2.lstrip())  

  javatpoint       javatpoint          After stripping all leading whitespaces:  javatpoint   javatpoint

After stripping, all the whitespaces are removed, and now the string looks like the below:

15) Why do we use join() function in Python?

The join() is defined as a string method which returns a string value. It is concatenated with the elements of an iterable. It provides a flexible way to concatenate the strings. See an example below.

  str = "Rohan"  str2 = "ab"  # Calling function    str2 = str.join(str2)    # Displaying result    print(str2)  

Output:

  aRohanb

16) Give an example of shuffle() method?

This method shuffles the given string or an array. It randomizes the items in the array. This method is present in the random module. So, we need to import it and then we can call the function. It shuffles elements each time when the function calls and produces different output.

  import random    list = [12,25,15,65,58,14,5,];  print(list)  random.shuffle(list)  print ("Reshuffled list : \n",  list)  

  [12, 25, 15, 65, 58, 14, 5]   Reshuffled list :   [58, 15, 5, 65, 12, 14, 25]

17) What is the use of break statement?

It is used to terminate the execution of the current loop. Break always breaks the current execution and transfer control to outside the current block. If the block is in a loop, it exits from the loop, and if the break is in a nested loop, it exits from the innermost loop.

  even = [2,4,6,8,10,11,12,14]  odd = 0  for val in even:      if val%2!=0:          odd = val          break      print(val)  print("odd value found",odd)  

  2  4  6  8  10  odd value found 11

Python Break statement flowchart.

18) What is tuple in Python?

A tuple is a built-in data collection type. It allows us to store values in a sequence. It is immutable, so no change is reflected in the original data. It uses () brackets rather than [] square brackets to create a tuple. We cannot remove any element but can find in the tuple. We can use indexing to get elements. It also allows traversing elements in reverse order by using negative indexing. Tuple supports various methods like max(), sum(), sorted(), Len() etc.

To create a tuple, we can declare it as below.

  # Declaring tuple  tup = (2,4,6,8)  # Displaying value  print(tup)    # Displaying Single value  print(tup[2])  

  (2, 4, 6, 8)  6

It is immutable. So updating tuple will lead to an error.

  # Declaring tuple  tup = (2,4,6,8)  # Displaying value  print(tup)    # Displaying Single value  print(tup[2])    # Updating by assigning new value  tup[2]=22  # Displaying Single value  print(tup[2])  

     tup[2]=22   TypeError: 'tuple' object does not support item assignment   (2, 4, 6, 8)

19) Which are the file related libraries/modules in Python?

The Python provides libraries/modules that enable you to manipulate text files and binary files on the file system. It helps to create files, update their contents, copy, and delete files. The libraries are os, os.path, and shutil.

Here, os and os.path - modules include a function for accessing the filesystem

while shutil - module enables you to copy and delete the files.

20) What are the different file processing modes supported by Python?

Python provides three modes to open files. The read-only, write-only, read-write and append mode. 'r' is used to open a file in read-only mode, 'w' is used to open a file in write-only mode, 'rw' is used to open in reading and write mode, 'a' is used to open a file in append mode. If the mode is not specified, by default file opens in read-only mode.

Read-only mode : Open a file for reading. It is the default mode.
Write-only mode: Open a file for writing. If the file contains data, data would be lost. Other a new file is created.
Read-Write mode: Open a file for reading, write mode. It means updating mode.
Append mode: Open for writing, append to the end of the file, if the file exists.

Interview :: python

Note: You don't need to import any extra module to use these functions for removing an element from the list.