python list

Author: hashfx

DSA-Python/DataStructures/list.py

@@ -0,0 +1,115 @@
+''' 
+LISTS
+    A list is a data structure in Python that is a mutable, or changeable, ordered sequence of elements
+
+Advantage of List over Linked List:
+    Elements can be accessed through their index value
+
+BigO of Array:
+    Indexing -----> O(1)
+    Insert/Delete element at Start -----> O(n)
+    Insert/Delete element at End -----> O(1)
+    Insert element at Middle -----> O(n)
+'''
+
+# Empty List
+list = []
+print(f"This is an Empty List: {list}\n")
+
+# List with Elements
+list = [1, 2, 3.1, "A"]
+print(f"Elements of the list are: {list}\n")
+
+
+''' Adding elements '''
+
+print("**********Adding Elements**********", end="\n\n")
+
+#add as a single element
+list.append(["B", 4]) 
+print("Appended List ", list, end="\n\n")
+
+#add as different elements
+list.extend([5, 'E']) 
+print("Entended List ", list, end="\n\n")
+
+#add element at 1st Index
+list.insert(0, 0) 
+list.insert(5, "F") 
+print("Inserted Element ", list, end="\n\n")
+
+
+''' Deleting Elements '''
+
+print("**********Deleting Elements**********", end="\n\n")
+#delete element at index 5
+del list[5] 
+print("Deleted element ", list, end="\n\n")
+
+#remove element with value '<val>'
+list.remove('E') 
+print("Removed element ", list, end="\n\n")
+
+#pop element from list at i^th index
+a = list.pop(1) 
+print('Popped Element: ', a, ' List remaining: ', list, end="\n\n")
+
+#empty the list
+list.clear() 
+print("Empty List ", list, end="\n\n")
+
+
+''' Accessing Elements '''
+
+print("**********Accessing Elements**********", end="\n\n")
+
+list = [1, 2, 3.5, "A", True]
+print("This is new list ", list, end="\n\n")
+
+#access elements one by one
+print("Accessing all Elements one by one\n")
+for element in list: 
+    print(element, end="\n")
+
+#access all elements
+print("\nAccessing all elements\n")
+print(list, end="\n\n") 
+
+#access index i element
+print("Element at index=2 is", list[2], end="\n\n") 
+
+#access elements from 0 to 1 and exclude 2
+print("Elements from index(0 to 1) are ", list[0:2], end="\n\n") 
+
+#access elements in reverse
+print("Elements in reverse order ", list[::-1], end="\n\n") 
+
+
+''' 
+Other Functions 
+    len() : returns length of the list.
+    index() : finds index value of value passed where it has been encountered the first time.
+    count()  : finds count of the value passed to it.
+    sorted() and sort() : to sort the values of the list. 
+    sorted() has a return type whereas the sort() modifies the original list.
+'''
+
+print("**********Other Functions**********", end="\n\n")
+
+list = [1, 2, 3, 10, 20, 50]
+
+#find length of list
+print("No of elements in the list ", len(list), end="\n\n") 
+
+#find index of element that occurs first
+print("Index of element 20 is ", list.index(20), end="\n\n") 
+
+#find count of the element
+print(f"Elements has been repeated {list.count(10)} time", end="\n\n")
+
+#print sorted list but not change original
+print("Sorted list is [AESC] ", sorted(list), end="\n\n") 
+
+#sort original list
+list.sort(reverse=True) 
+print("Sorted list is [DESC]", list, end="\n\n")