Question

Explain the difference among list, tuple, and dictionary. Why does python have all of them?

Answer 1

Lists: Lists are used to store same or different type of elements. Elements in a list are indexed from 0. ists are mutable i.e. we can change the content of items during execution. We can add elements, we can delete elements, we can sort them also. A list is denoted by [ ] in python. Names 'a', 'b', 'c'] for example if we want to store names of the people or we want to store students marks we may use lists and we can managethese kind of data easily. Marks [90, 80,85 ] we can perform several operations on lists. Some are max0, min0, sumO

Tuples: Tuples are just like lists but they are immutable, it means once values are stored into a tuple we cannot change its values. They are fixed. we may need it in python when you want store some values and we need not change them during entire execution of program. In these cases tuples will be helpful and easy to manage by python. A tuple is denoted by () in python. It's index will also start at O. Ex: for example if we want to store days of a week which need not be changed we can use tuple. days 'Monday', Tuesday', 'Wednesday', "Thursday', 'Friday', 'Saturday', 'Sunday')

Dictionaries: Just as an actual dictionary has a word and its meaning, Python dictionaries will have key-value pairs. Dictionaries are very much useful in so many situations. They are denoted by curly braces. Once we see an example it will be more clear. suppose you want to store number of times each word is occurred in a particular file, using above data structures lists and tuples wouldn't be very good way. But in case of dictionaries it is as follows words count the': 10, 'and':3, 'apple':1, 'cat': 2) now if we want to see how many times apple is there, words_countl'apple'] gives 2. storing this kind with dictionaries. That's why python have it.