The built-in functions repr() and str() respectively call object.__repr__(self) and object.__str__(self) methods. First function computes official representation of the object, while second returns informal representation of the object. Result of both functions is same for integer object. >>> x = 1 >>> repr(x) '1' >>> str(x) '1' However, it is not the case for string object. >>> x = "Hello" >>> repr(x) "'Hello'" >>> str(x) 'Hello' Return value of repr() of a string object can be evaluated by eval() function and results in valid string object. However, result of str() can not be evaluated. ... Read More

Presence of a certain file in the computer can be verified by two ways using Python code. One way is using isfile() function of os.path module. The function returns true if file at specified path exists, otherwise it returns false. >>> import os >>> os.path.isfile("d:\Package1\package1\fibo.py") True >>> os.path.isfile("d:/Package1/package1/fibo.py") True >>> os.path.isfile("d:onexisting.txt") Note that to use backslash in path, two backslashes have to be used to escape out of Python string. Other way is to catch IOError exception that is raised when open() function has string argument corresponding to non-existing file. try: fo = open("d:onexisting.txt", ... Read More

In this article, we will show you how to remove the index list elements from the original list using python. Now we see 2 methods to accomplish this task − Using pop() method Using del keyword Assume we have taken a list containing some elements. We will remove the index list elements from the main list using different methods as specified above. Note We must sort the indices list in descending order because removing elements from the beginning will change the indices of other elements, and removing another element will result in an incorrect result due to misplaced ... Read More

In Python, a list is an ordered sequence that can hold several object types such as integer, character, or float. In this article, we will show you how to join the list of lists(nested lists) using python. Now we see 4 methods to accomplish this task − Using nested for loop Using List comprehension Using sum() function Using NumPy module Assume we have taken a list of lists containing some elements. We will join those list of lists and return the result using different methods as specified above. Method 1: Using nested for loop Algorithm (Steps) Create a ... Read More

In this article, we will show you the remove an element from a list by index using Python. Here we see 4 methods to accomplish this task − Using the del keyword to remove an element from the list Using the pop() function to remove an element from the list Using slicing to remove an element from the list Using indices to remove multiple elements from the list Assume we have taken a list containing some elements. We will remove a specific item from a list by giving the index value using the above-specified methods. Method 1: Using ... Read More

The built-in function tuple() converts a Python string into tuple of individual characters. It also turns a list object into a tuple.>>> tuple("TutorialsPoint") ('T', 'u', 't', 'o', 'r', 'i', 'a', 'l', 's', 'P', 'o', 'i', 'n', 't') >>> L1=[45, 32, 100, 10, 24, 56] >>> tuple(L1) (45, 32, 100, 10, 24, 56)

Position of an element in a list (any sequence data type for that matter) is obtained by index() method. This method finds first instance of occurrence of given element.>>> L1=[45, 32, 100, 10, 24, 56] >>> L1.index(24) 4

Both List and Tuple are called as sequence data types of Python. Objects of both types are comma separated collection of items not necessarily of same type.SimilaritiesConcatenation, repetition, indexing and slicing can be done on objects of both types>>> #list operations >>> L1=[1, 2, 3] >>> L2=[4, 5, 6] >>> #concatenation >>> L3=L1+L2 >>> L3 [1, 2, 3, 4, 5, 6] >>> #repetition >>> L1*3 [1, 2, 3, 1, 2, 3, 1, 2, 3] >>> #indexing >>> L3[4] 5 >>> #slicing >>> L3[2:4] [3, 4]>>> #tuple operations >>> T1=(1, 2, 3) >>> T2=(4, 5, 6) >>> #concatenation >>> T3=T1+T2 >>> ... Read More

List and Tuple are called as sequence data types of Python. Objects of both types are comma separated collection of items not necessarily of same type. However, main difference between list and tuple is that list object is mutable whereas tuple object is immutable. Immutable object can not be modified once it is created in memory. Hence it is not possible to add, modify or remove item from tuple object. On the other hand these operations can be performed on a list.

Python sequence, including list object allows indexing. Any element in list can be accessed using zero based index. If index is a negative number, count of index starts from end.  As we want second to last element in list, use -2 as index.>>> L1=[1,2,3,4,5] >>> print (L1[-2]) 4