First, the sequence is a data storage for storing a series of data in memory, the sequence is used to store a plurality of contiguous memory space worth. For example, a sequence of integers [10,20,30], illustrated as follows:
Everything in the object Python3 a = [10,20,30]
Integer object is stored in the sequence of addresses, instead of the value of an object, used in the sequence are Python structure:
Strings, lists, dictionaries, tuples, collection
List: When to add and delete elements in the list, the list will automatically memory management, reducing the burden on the programmer, but a large number of list elements moving, inefficient, it is generally recommended to add at the end.
append () method:
Example:
list = [1,2,4]
list.append(5)
print(list)
+ Operator operation
Not really add elements in the tail, but to create a new list object; a copy of the original elements and elements of the new list of lists into a new list is not recommended:
Example:
a = [1]
a = a + [2]
print(a)
extend (Method):
Add all the elements of the target list to the end of the list, are in situ operation, not create a new list object.
a = [1,2]
a.extend([3])
insert () insert elements
Use insert () method will be developed at any position of the elements into a list of objects, so that all the elements will move into the rear position, can affect processing speed. Similar function as well as remove (), pop (), del ()
a = [1,2,3]
a.insert(1,20)
print(a)
Multiplication list expansion:
a = [1,2,3]
b = a*3
print(b)
Delete list:
del Delete
a = [1,2,3,4]
of the a [1]
print(a)
pop () method removes and returns the element at the location, if not specified, the default position of the last element in the list of actions
a = [1,2,3,4]
a.pop()
print(a)
remove () method removes the first occurrence of the specified element, if that element exists an exception is thrown
a = [1,2,3,4]
a.remove(3)
print(a)