List have many different methods . Some of that are available with list object in Python programming are:
index()
In simple
terms, the index() method finds the given element in a list and returns its
position. If the same element is present more than once, the method returns the
index of the first occurrence of the element.
The syntax of the index() method is:
list.index(element)
Example
p = ['p', 'r', 'o', 'g', 'r', 'a', 'm']
index = p.index('o')
print('The index of o:', index)
index = p.index('r')
print('The index of r:', index)
Output
The index of o: 2
The index of r: 1
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append()
To add an
item to the end of the list, use the append() method.
The syntax of the append() method is:
list.append(item)
Example
list = ["aaa", "bbb", "ccc"]
list.append("ooo")
print(list)
Output
['aaa', 'bbb', 'ccc', 'ooo']
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insert()
The insert() method inserts an element to the list at
a given index.
The syntax of insert() method is
list.insert(index, element)
Example
list = ['aaa', 'bbb', 'ccc']
list.insert(1, "ooo")
print(list)
Output
['aaa', 'ooo', 'bbb', 'ccc']
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copy()
The copy() method returns a shallow copy of the list. It gives shallow copy that means modification in new list will not affect old list
The syntax of copy() method is:
new_list = list.copy()
Example
l = ['aaa', 'bbb', 'ccc', 'ooo']
x = l.copy()
print(l)
Output
['aaa', 'bbb', 'ccc', 'ooo']
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extend()
The extend() method adds the specified list elements
(or any iterable) to the end of the current list.
The syntax for extend() method
list.extend(seq)
Example
b1 = ['cse', 'ece', 'eee']
b2 = ['mec', 'civ', 'aero']
b1.extend(b2)
print(b1)
print(b2)
Output
['cse', 'ece', 'eee', 'mec', 'civ', 'aero']
['mec', 'civ', 'aero']
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count()
Python list method count() returns count of how many times obj occurs
in list.
Syntax
The syntax for count() method
list.count(obj)
Example
L = [123, 'apple', 'banana', 'orange', 123];
print( "Count for 123 : ", L.count(123))
print ("Count for banana : ", L.count('banana'))
Output
Count for 123 : 2
Count for banana : 1
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remove()
The remove() method removes the first occurrence of
the element with the specified value.
Syntax
list.remove(elmnt)
Example
b = ['cse', 'ece', 'eee']
b.remove("ece")
print(b)
Output
['cse', 'eee']
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pop()
The pop() method removes the element at the specified
position.
Syntax
list.pop(pos)
Example
languages = ['Python', 'Java', 'C++', 'Dotnet', 'C']
return_value = languages.pop(3)
print('Return Value:', return_value)
print('Updated List:', languages)
Output
Return Value: Dotnet
Updated List: ['Python', 'Java', 'C++', 'C']
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reverse()
The
reverse() method reverses the sorting order of the elements.
Syntax
list.reverse()
Example
b = ['cse', 'ece', 'eee','it','aero']
print('Original List:', b)
b.reverse()
print('Updated List:', b)
Output
Original List: ['cse', 'ece', 'eee', 'it', 'aero']
Updated List: ['aero', 'it', 'eee', 'ece', 'cse']
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sort()
The sort() method sorts the elements of a given list
in a specific order - Ascending.
The syntax of sort() method is:
list.sort(key=..., reverse=...)
Alternatively, you can also use Python's in-built
function sorted() for the same purpose.
sorted(list, key=..., reverse=...)
Example
b = ['cse', 'ece', 'eee','it','aero']
b.sort()
print('Sorted List:', b)
Output
Sorted List: ['aero', 'cse', 'ece', 'eee', 'it']
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len()
Python list function len() returns the number of
elements in the list.
Syntax
The syntax for len() method
len(list)
Example
b = ['cse', 'ece', 'eee','it','aero']
c = ['red','green','blue']
print( "First list length : ", len(b))
print ("Second list length : ", len(c))
Output
First list length : 5
Second list length : 3
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Nested
List
A list can contain any sort object, even another list
(sublist), which in turn can contain sublists themselves, and so on. This is
known as nested list. A nested list is created by placing a comma-separated
sequence of sublists.
Example1
L = ['a', ['bb', ['ccc', 'ddd'], 'ee', 'ff'], 'g',
'h']
Example2
b = ['cse', 'ece', ['eee','it',['aero','mech']],'civ','h&s']
print(b[2])
print(b[2][2])
print(b[2][2][0])
Output
['eee', 'it', ['aero', 'mech']]
['aero', 'mech']
aero
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