list.append(obj))

Add a new object at the end of the list

list.count(obj)

Count the number of times an element appears in the list

list.extend(list1)

Append multiple values in another sequence at the end of the list (extend the original list with a new list)

list.index(obj)

Find the index position of the first match of a value from the list

list.insert(index, obj)

Insert objects into the list

list.pop([index=-1])

Removes an element from the list (the last element by default) and returns the value of that element

list.remove(obj)

Remove the first match for a value in the list

list.reverse()

Elements in reverse list

list.sort(cmp=None, key=None, reverse=False)

Sort the original list

List.append() method

describe

The append() method is used to add a new object at the end of the list.

grammar

list.append(obj)

parameter

• obj – the object added to the end of the list.

Return value

There is no return value for this method, but the original list will be modified.

example

aList = [123, 'xyz', 'zara', 'abc'];
aList.append( 2009 );
print "Updated List : ", aList;

Updated List :  [123, 'xyz', 'zara', 'abc', 2009]

List.count() method

describe

The count() method is used to count the number of times an element appears in the list.

grammar

list.count(obj)

parameter

• obj – objects counted in the list.

Return value

Returns the number of times an element appears in the list.

example

aList = [123, 'xyz', 'zara', 'abc', 123];

print "Count for 123 : ", aList.count(123);
print "Count for zara : ", aList.count('zara');

Count for 123 :  2
Count for zara :  1

List.extend() method

describe

The extend() function is used to append multiple values in another sequence at the end of the list at one time (extend the original list with a new list)

grammar

list.extend(seq)

parameter

• seq – list of elements.

Return value

The method does not return a value, but adds new list content to the existing list.

example

#!/usr/bin/python

aList = [123, 'xyz', 'zara', 'abc', 123];
bList = [2009, 'manni'];
aList.extend(bList)

print "Extended List : ", aList ;

Extended List :  [123, 'xyz', 'zara', 'abc', 123, 2009, 'manni']

List.index() method

describe

The index() function is used to find the index position of the first match of a value from the list.

grammar

list.index(x[, start[, end]])

parameter

• x -- the object to find.
• start -- optional, the starting position of the search.
• End -- optional, the end position of the search.

Return value

This method returns the index location of the lookup object, and throws an exception if the object is not found.

example

aList = [123, 'xyz', 'runoob', 'abc']

print "xyz Index location: ", aList.index( 'xyz' )
print "runoob Index location : ", aList.index( 'runoob', 1, 3 )

xyz index location: 1
 runoob index location: 2

List.insert() method

describe

The insert() function inserts the specified object into the specified location in the list.

grammar

list.insert(index, obj)

parameter

• Index – the index location where the object obj needs to be inserted.
• obj – the object to insert into the list.

Return value

The method does not return a value, but inserts the object at the location specified in the list.

example

aList = [123, 'xyz', 'zara', 'abc']  
aList.insert( 3, 2009)  
print "Final List : ", aList

Final List : [123, 'xyz', 'zara', 2009, 'abc']

List.pop() method

describe

The pop() function removes an element from the list (the last element by default) and returns the value of that element.

grammar

list.pop([index=-1])

parameter

• obj – optional parameter. To remove the index value of the list element, it cannot exceed the total length of the list. The default value is index=-1. Delete the last list value.

Return value

This method returns the element object removed from the list.

example

list1 = ['Google', 'Runoob', 'Taobao'] list_pop=list1.pop(1) 
print "Deleted items are :", list_pop 
print "The list is now : ", list1

Deleted item is: Runoob
 The list is now: ['google ',' Taobao ']

List.remove() method

describe

The remove() function removes the first match for a value in the list.

grammar

list.remove(obj)

parameter

• obj – the object to be removed from the list.

Return value

The method does not return a value, but removes the first match for a value in the list.

example

list1 = ['Google', 'Runoob', 'Taobao', 'Baidu']
list1.remove('Taobao')
print ("The list is now : ", list1)
list1.remove('Baidu')
print ("The list is now : ", list1)

The list is now: ['google ',' runoob ',' Baidu ']
The list is now: ['google ',' runoob ']

List.reverse() method

describe

The reverse() function is used to reverse the elements in the list.

grammar

list.reverse()

parameter

• NA.

Return value

The method does not return a value, but sorts the elements of the list in reverse.

example

#!/usr/bin/python3

list1 = ['Google', 'Runoob', 'Taobao', 'Baidu']
list1.reverse()
print ("After list reversal: ", list1)

After the list is reversed: ['baidu ',' Taobao ',' runoob ',' Google ']

List.sort() method

describe

The sort() function is used to sort the original list. If you specify parameters, the comparison function specified by the comparison function is used.

grammar

list.sort( key=None, reverse=False)

parameter

• key - the element mainly used for comparison. There is only one parameter. The specific function parameter is taken from the iteratable object. Specify an element in the iteratable object to sort.
• Reverse - collation, reverse = True descending, reverse = False ascending (default).

Return value

This method does not return a value, but sorts the objects in the list.

example

aList = ['Google', 'Runoob', 'Taobao', 'Facebook'] aList.sort() 
print ( "List : ", aList)

List :  ['Facebook', 'Google', 'Runoob', 'Taobao']

Descending output list

# list 
vowels = ['e', 'a', 'u', 'o', 'i']  
# Descending order 
vowels.sort(reverse=True)  
# Output results 
print ( 'Descending output:', vowels )

Output in descending order: ['u ',' o ',' I ',' e ',' a ']

Output the list by specifying the sorting of elements in the list

# Get the second element of the list 
def takeSecond(elem):    
    return elem[1]  
# list 
random = [(2, 2), (3, 4), (4, 1), (1, 3)]  
# Specify the second element sort 
random.sort(key=takeSecond)  
# Output category 
print ('Sort list:', random)

Sort list: [(4, 1), (2, 2), (1, 3), (3, 4]]

List.clear() method

describe

The clear() function is used to clear the list, similar to del a [:].

grammar

list.clear()

parameter

• None.

Return value

The method does not return a value.

example

list1 = ['Google', 'Runoob', 'Taobao', 'Baidu']
list1.clear()
print ("After the list is cleared : ", list1)

After the list is cleared: []

List.copy() method

describe

The copy() function copies the list, similar to a [:].

grammar

list.copy()

parameter

• None.

Return value

Returns the new list after replication.

example

list1 = ['Google', 'Runoob', 'Taobao', 'Baidu']
list2 = list1.copy()
print ("list2 list: ", list2)

list2 list:  ['Google', 'Runoob', 'Taobao', 'Baidu']