Python - List List methods
Introduction
reverse method reverses the list in-place.
The extend and pop methods insert multiple items at and delete an item from the end of the list, respectively.
There is a reversed built-in function that works much like sorted and returns a new result object.
It must be wrapped in a list call in both 2.X and 3.X here because its result is an iterator that produces results on demand:
Demo
L = [1, 2] L.extend([3, 4, 5]) # Add many items at end (like in-place +) print( L ) print( L.pop() ) # Delete and return last item (by default: -1) print( L ) L.reverse() # In-place reversal method print( L ) print( list(reversed(L)) ) # Reversal built-in with a result (iterator) # from www . j av a 2 s . c o m
Result
extend method adds many items, and append method adds one.
The list pop method is often used in conjunction with append to implement a quick last-in-first-out (LIFO) stack structure.
Demo
L = [] L.append(1) # Push onto stack L.append(2) # from w w w.j a v a 2 s. c om print( L ) print( L.pop() ) # Pop off stack print( L )
Result
The pop method accepts an optional offset of the item to be deleted and returned. The default is the last item at offset -1.
More method demonstration:
Demo
L = ['test','eggs', 'ham'] print( L.index('eggs') ) # Index of an object (search/find) L.insert(1, 'toast') # Insert at position print( L ) L.remove('eggs') # Delete by value print( L ) print( L.pop(1) ) # Delete by position print( L ) L.count('test') # Number of occurrences # w w w .j ava 2 s . com
Result
