str DataType:
String:
- Group of characters or sequence of characters is known as String.
- We can represent the Strings in Python language by using single quotes (‘ ‘) or by using double quotes(“ “) or triple quotes(‘’’ ‘’’) and (“”” “””).
- Single quotes are used to represent one line String.
- Triple quotes are used to represent multiple lines.
- Every character in the String Object is represented with unique index.
- Python Strings are supporting both the +ve(Forward) indexing and –ve(Backward) indexing.
- +ve index starts with 0(zero) whereas -ve index starts from -1.
Example1:
x= 'siva'
print(x)
y= "krishna"
print(y)
z= '''hai,
this is siva krishna'''
print(z)
a= """
hai,
welcome to my blog.
tanq for follow my blog"""
print(a)
Output:
siva
Krishna
hai,
this is siva Krishna
hai,
welcome to my blog.
tanq for follow my blog.
Note:
- Actually string (str) object is a immutable object, not modified. But reading the data by using indexes.
Example2:
s1="sivakrishna"
print(s1)
print(id(s1))
print(type(s1))
print(len(s1))
Output:
sivakrishna
55790896
<class 'str'>
11
Note:
- len( ) is a pre-defined function in Builtin module.
- Return the number of items/elements in a container/string.
- Reading the data from the string by using indexes.
Example3:
s2="sivakrishna"
print(len(s2)) ---> return the number of characters in a given
string.
print(s2[1]) ---> forward
index, starting from 0
print(s2[-2]) ---> backward
index, starting from -1
Output:
11
i
n
Python support slice(:) operator.
Syntax:
- [n1:n2] --- > n1 is lower bound value/n1 is a beginning index is inclusive and n2 is a upper bound value/n2 is a ending index is exclusive.
- [n1: ] ---> n1 is lower bound value and up to ending value in a string.
Example4:
s3="sivakrishna"
print(s3)
print(len(s3))
print(s3[2:])
print(s3[2:5])
print(s3[-6:-2])
Output:
sivakrishna
11
vakrishna
vak
rish
Note:
- First number is always lower limit.
- Second number is always upper limit.
Example5:
s4="sivakrishna"
print(s4)
print(len(s4))
print(s4[3:1])
print(s4[-2:-6])
Output:
sivakrishna
11
No output
No output
Some other methods in string
Example6:
a='siva'
b='KRISHNA'
print(a+b)
print(len(a))
print(a.upper())
print(b.lower())
print(a.startswith('si'))
print(b.startswith('kri'))
print(b.startswith('KRI'))
print(a.replace('siva','rama'))
print(b.replace('KRISHNA','seetha'))
Output:
sivaKRISHNA
4
SIVA
krishna
True
False
True
rama
seetha
