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In this tutorial we will learn how to find position of a character in a string in Python . Python string provides some built-in methods to find position of a character in a string . They are as follows –
- Python string
find()method - Python string
rfind()method - Python string
index()method - Python string
rindex()method
Here we will use the string as “Coding Conception” . From the below image we can see what is the position of every character in the string .
Now we will discuss about all the previously mentioned methods with examples –
Python string find() method
It will return the index number for the first occurrence of a character in a string . If the character is not found then it will return -1 .
Syntax of find() method
string.find(sub, start ,end)
Parameters of find() method
- sub = It is the substring whose position we want to know in the string .
- start = Optional . It is an integer number specifying from where
find()method will start searching . This number is included and its default value is 0 . - end = Optional . It is an integer number specifying the position where
find()method will end searching . This number is excluded and its default value is length of the string .
Return type of find() method
It returns an integer number .
Examples of find() method
Example 1:
mystring = "Coding Conception"
# finding the position of first "C"
print("position of first 'C' =",mystring.find("C"))
# finding the position of first "on"
print("position of first 'on' =",mystring.find("on"))position of first 'C' = 0 position of first 'on' = 8
Example 2:
# finding the position of first "C" starting from 4 to 10
print("position of first 'C' from 4 to 10 =",mystring.find("C",4,10))
# finding the position of first "on" starting from 10 to end
print("position of first 'on' from 10 to end =",mystring.find("on",10))position of first 'C' from 4 to 10 = 7 position of first 'on' from 10 to end = 15
Example 3:
# if character is not found
print("position of 'A' =",mystring.find("A"))position of 'A' = -1
Python string rfind() method
It will return the index number for the last occurrence of a character in a string . If the character is not found then it will return -1 . Actually rfind() method iterates a string from right side .
Syntax of rfind() method
string.rfind(sub, start ,end)
Parameters of rfind() method
- sub = It is the substring whose position we want to know in the string .
- start = Optional . It is an integer number specifying from where
rfind()method will start searching . This number is included and its default value is 0 . - end = Optional . It is an integer number specifying the position where
rfind()method will end searching . This number is excluded and its default value is length of the string .
Return type of rfind() method
It returns an integer number .
Examples of rfind() method
Example 1:
mystring = "Coding Conception"
# finding the position of last "C"
print("position of last 'C' =",mystring.rfind("C"))
# finding the position of last "on"
print("position of last 'on' =",mystring.rfind("on"))position of last 'C' = 7 position of last 'on' = 15
Example 2:
# finding the position of last "C" starting from 0 to 2
print("position of last 'C' from 0 to 2 =",mystring.rfind("C",0,2))
# finding the position of last "on" starting from 0 to 10
print("position of last 'on' from 0 to 10 =",mystring.rfind("on",0,10))position of last 'C' from 0 to 2 = 0 position of last 'on' from 0 to 10 = 8
Example 3:
# if character is not found
print("position of 'A' =",mystring.rfind("A"))position of 'A' = -1
Python string index() method
It will return the index number for the first occurrence of a character in a string . If the character is not found then it will raise ValueError .
Syntax of index() method
string.index(sub, start ,end)
Parameters of index() method
- sub = It is the substring whose position we want to know in the string .
- start = Optional . It is an integer number specifying from where
index()method will start searching . This number is included and its default value is 0 . - end = Optional . It is an integer number specifying the position where
index()method will end searching . This number is excluded and its default value is length of the string .
Return type of index() method
It returns an integer number .
Examples of index() method
Example 1:
mystring = "Coding Conception"
# finding the position of first "C"
print("position of first 'C' =",mystring.index("C"))
# finding the position of first "on"
print("position of first 'on' =",mystring.index("on"))position of first 'C' = 0 position of first 'on' = 8
Example 2:
# finding the position of first "C" starting from 4 to 10
print("position of first 'C' from 4 to 10 =",mystring.index("C",4,10))
# finding the position of first "on" starting from 10 to end
print("position of first 'on' from 10 to end =",mystring.index("on",10))position of first 'C' from 4 to 10 = 7 position of first 'on' from 10 to end = 15
Example 3:
# if character is not found
print("position of 'A' =",mystring.index("A"))---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
C:\Users\RAJKUM~1\AppData\Local\Temp/ipykernel_3724/138207988.py in <module>
1 # if character is not found
----> 2 print("position of 'A' =",mystring.index("A"))
ValueError: substring not found
Python string rindex() method
It will return the index number for the last occurrence of a character in a string . If the character is not found then it will raise ValueError . Actually rindex() method iterates a string from right side .
Syntax of rindex() method
string.rindex(sub, start ,end)
Parameters of rindex() method
- sub = It is the substring whose position we want to know in the string .
- start = Optional . It is an integer number specifying from where
rindex()method will start searching . This number is included and its default value is 0 . - end = Optional . It is an integer number specifying the position where
rindex()method will end searching . This number is excluded and its default value is length of the string .
Return type of rindex() method
It returns an integer number .
Examples of rindex() method
Example 1:
mystring = "Coding Conception"
# finding the position of last "C"
print("position of last 'C' =",mystring.rindex("C"))
# finding the position of last "on"
print("position of last 'on' =",mystring.rindex("on"))position of last 'C' = 7 position of last 'on' = 15
Example 2:
# finding the position of last "C" starting from 0 to 2
print("position of last 'C' from 0 to 2 =",mystring.rindex("C",0,2))
# finding the position of last "on" starting from 0 to 10
print("position of last 'on' from 0 to 10 =",mystring.rindex("on",0,10))position of last 'C' from 0 to 2 = 0 position of last 'on' from 0 to 10 = 8
Example 3:
# if character is not found
print("position of 'A' =",mystring.rindex("A"))---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
C:\Users\RAJKUM~1\AppData\Local\Temp/ipykernel_3724/2863189514.py in <module>
1 # if character is not found
----> 2 print("position of 'A' =",mystring.rindex("A"))
ValueError: substring not found
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