In this article, we will focus only on sequences<\/strong>. So, let\u2019s get started.<\/p>\n In Python programming, sequences are a generic term<\/strong> for an ordered set<\/strong> which means that the order in which we input<\/strong> the items will be the same when we access<\/strong> them.<\/p>\n Python supports six<\/strong> different types of sequences. These are strings<\/strong>, lists<\/strong>, tuples<\/strong>, byte<\/strong> sequences<\/strong>, byte arrays<\/strong>, and range objects<\/strong>. We will discuss each of them.<\/p>\n Strings are a group of characters<\/strong> written inside a single or double-quote<\/strong>s. Python does not have a character type<\/strong> so a single character inside quotes is also considered as a string<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Strings are immutable<\/strong> in nature so we can reassign<\/strong> a variable to a new string but we can\u2019t<\/strong> make any changes<\/strong> in the string<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Python lists are similar to an array but they allow us to create<\/strong> a heterogeneous collection<\/strong> of items inside a list<\/strong>. A list can contain numbers<\/strong>, strings<\/strong>, lists<\/strong>, tuples<\/strong>, dictionaries<\/strong>, objects<\/strong>, etc.<\/p>\n Lists are declared by using square brackets<\/strong> around comma-separated<\/strong> items.<\/p>\n Syntax:<\/strong><\/p>\n Lists<\/strong> are mutable<\/strong> which makes it easier to change<\/strong> and we can quickly modify<\/strong> a list by directly accessing<\/strong> it.<\/p>\n Code:<\/strong><\/p>\n Output: <\/strong><\/p>\n Tuples are also a sequence<\/strong> of Python objects<\/strong>. A tuple is created by separating<\/strong> items with a comma<\/strong>. They can be optionally put inside the parenthesis ()<\/strong> but it is necessary to put parenthesis in an empty tuple<\/strong>.<\/p>\n A single item tuple<\/strong> should use a comma<\/strong> in the end.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Tuples are also immutable<\/strong> like strings<\/strong> so we can only reassign<\/strong> the variable<\/strong> but we cannot change<\/strong>, add<\/strong> or remove elements<\/strong> from the tuple<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n The bytes()<\/strong> function in Python is used to return<\/strong> an immutable<\/strong> bytes sequence<\/strong>. Since they are immutable, we cannot modify<\/strong> them.<\/p>\n If you want a mutable byte sequence<\/strong>, then it is better to use byte arrays<\/strong>. This is how we can create a byte of a given integer size<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Iterables can be converted into bytes<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n For strings, we have to provide the encoding<\/strong> in the second parameter<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Byte arrays are similar<\/strong> to bytes sequence<\/strong>. The only difference here is that byte arrays are mutable<\/strong> while bytes sequences are immutable<\/strong>. So, it also returns<\/strong> the bytes object<\/strong> the same way.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Since byte arrays are mutable<\/strong>, let\u2019s try changing a byte<\/strong> from the array<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n range()<\/strong> is a built-in function in Python that returns us a range object<\/strong>. The range object is nothing but a sequence of integers<\/strong>. It generates the integers within the specified start<\/strong> and stop range<\/strong>.<\/p>\n Let\u2019s see this with an example.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Since range object generates integers<\/strong>, we can access them by iterating using a for loop<\/strong>.<\/p>\n Code: <\/strong><\/p>\n Output:<\/strong><\/p>\n The first argument is the starting range<\/strong>, the second argument is the stopping range<\/strong> and the third argument tells how many steps to take<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Let\u2019s discuss the operations we can perform on the sequences.<\/p>\n The operator (+)<\/strong> is used to concatenate<\/strong> the second element<\/strong> to the first<\/strong>.<\/p>\n For example<\/strong> –<\/strong> [1,3,4] + [1,1,1] will evaluate to [1,3,4,1,1,1].<\/p>\n We can concate<\/strong> all other sequences<\/strong> like this.<\/p>\n The operator (*)<\/strong> is used to repeat<\/strong> a sequence n number of times<\/strong>.<\/p>\n For example –<\/strong> (1,2,3) * 3 will evaluate to (1,2,3,1,2,3,1,2,3).<\/p>\n This also works on sequences<\/strong> other than tuples<\/strong>.<\/p>\n Membership operators (in)<\/strong> and (not in)<\/strong> are used to check whether<\/strong> an item is present<\/strong> in the sequence<\/strong> or not<\/strong>. They return True<\/strong> or False<\/strong>.<\/p>\n For example –<\/strong> \u2018la\u2019 in \u201cManilla\u201d evaluates to True and \u2018a\u2019 not in \u2018all\u2019 evaluates to False.<\/p>\n All the sequences in Python can be sliced<\/strong>. The slicing operator can take out<\/strong> a part<\/strong> of a sequence<\/strong> from the sequence.<\/p>\n For example –<\/strong><\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\n Let us discuss some of the useful functions we can use on sequences.<\/p>\n The len()<\/strong> function is very handy when you want to know the length<\/strong> of the sequence<\/strong>.<\/p>\n Code:<\/strong><\/p>\n Output:<\/strong><\/p>\nPython Sequences<\/h3>\n
Types of Python Sequences<\/h3>\n
Python Strings<\/h4>\n
name = \u201cTechVidvan\u201d\ntype(name)<\/pre>\n
city= \u2018China\u2019\nprint(city[2])\ncity[2] = \u2018a\u2019<\/pre>\n
\n\u00a0\u00a0<\/span>File “<stdin>”, line 3, in <module>
\nTypeError: ‘str’ object does not support item assignment<\/div>\nPython Lists<\/h4>\n
list1 = [1,2,3,4]\nlist2 = [\u2018red\u2019, \u2018green\u2019, \u2018blue\u2019]\nlist3 = [\u2018hello\u2019, 100, 3.14, [1,2,3] ]<\/pre>\n
list = [10,20,30,40]\nlist[1] = 100\nprint( list)<\/pre>\n
Python Tuples<\/h4>\n
tup = ()\nprint( type(tup) )\ntup = (1,2,3,4,5)\ntup = ( \u201c78 Street\u201d, 3.8, 9826 )\nprint(tup)<\/pre>\n
\n(’78 Street’, 3.8, 9826)<\/div>\ntup = (1,2,3,4,5)\ntup[2] = 10<\/pre>\n
\n\u00a0\u00a0<\/span>File “<stdin>”, line 2, in <module>
\nTypeError: ‘tuple’ object does not support item assignment<\/div>\nBytes Sequences in Python<\/h4>\n
size = 10\nb = bytes(size)\nprint( b )<\/pre>\n
print( bytes([4,2,1]) )<\/pre>\n
bytes(\u201cHey\u201d, \u2018utf=8\u2019)<\/pre>\n
Byte Arrays in Python<\/h4>\n
print( bytearray(4) )\nprint( bytearray([1, 2, 3, 4]) )\nprint( bytearray(\u2018Hola!\u2019, \u2018utf-8\u2019))<\/pre>\n
\nbytearray(b’\\x01\\x02\\x03\\x04′)
\nbytearray(b’Hola!’)<\/div>\na = bytearray([1,3,4,5])\nprint(a)\na[2] = 2\nprint(a)<\/pre>\n
\nbytearray(b’\\x01\\x03\\x02\\x05′)<\/div>\nPython range() objects<\/h4>\n
num = range(10)\nprint( type(num) )<\/pre>\n
for i in range(5):\n print(i)<\/pre>\n
\n1
\n2
\n3
\n4<\/div>\nfor i in range(4,16,2):\n print()<\/pre>\n
\n6
\n8
\n10
\n12
\n14<\/div>\nOperations on Python Sequences
![\"python](\"https:\/\/techvidvan.com\/tutorials\/wp-content\/uploads\/sites\/2\/2020\/01\/operations-on-python-sequences.jpg\")
<\/a><\/h3>\n1. Concatenation<\/h4>\n
2. Repeat<\/h4>\n
3. Membership Operators<\/h4>\n
4. Slicing Operator<\/h4>\n
print( \"The new york times\"[4:10] )\nprint( (1,2,3,4,5)[1:3] )<\/pre>\n
\n(2,3)<\/div>\nPython Sequence Functions
<\/a><\/h3>\n1. len()<\/h4>\n
len(\u201cThis is a sentence\u201d)<\/pre>\n