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Python find()

The find() function in python helps to return the position of the given substring. If they're more than one occurrence it will return the first occurrence. In case if the searched substring is not found it will return -1.

str.find(sub[, start[, end]] ) #where start & end must be an integers

find() Parameters:

The find() function takes three parameters. If start and end parameter is missing, it will take zero as starting index and lenght-1 as ending parameter.

Parameter Description Required / Optional
sub The substring whose index has to be found Required
start Position from where the searching should start in the string. Default is 0 Optional
end Position until the searching should happen. Default is the end of the string Optional

find() Return Value

The return value is always a integer value specifies the position or index of the substring.This method is similar to index() method,the difference is that index() throws an exception if the searched substring is not found.

Input Return Value
if substring found index value
if not substring found -1

Examples of find() method in Python

Example 1: How find() with no start and end argument?

string = 'What is the, what is the, what is the'

# first occurance of 'what is'(case sensitive)
result = string.find('what is')
print("Substring 'what is':", result)

# find returns -1 if substring not found
result = string.find('Hii')
print("Substring 'Hii ':", result)

# How to use find() in conditions
if (string.find('is,') != -1):
    print("Contains substring 'is,'")
    print("Doesn't contain substring")


Substring 'let it': 13
Substring 'small ': -1
Contains substring 'is,'

Example 2: How find() work with start and end arguments?

string = 'What is your name'

# Substring is searched in 'your name'
print(string.find('your name', 7)) 

# Substring is searched in ' is your' 
print(string.find('is your', 10))

# Substring is searched in 'what is'
print(string.find('what is', 8, 16))

# Substring is searched in 'is your'
print(string.find('is your ', 0, 14))