Substring search in Python

Question

Is there a function in Python to search for a string within a string in Python?

Answer 1

Use the "in" operator in python"

if "substring" not in string1:
    #continue code

Answer 2

string = "Hello Agnosticdev, I love Tutorials"
substring = "Agnosticdev"
 
# Straight forward approach for Python 2.7 and Python 3.6
# Executes the conditional statement when the substring is found
if substring in string:
	print ("Your substring was found!")

Answer 3

You can use the in operator:

if "blah" not in somestring: 
    continue

Answer 4

If it's just a substring search you can use string.find("substring").

You do have to be a little careful with find, index, and in though, as they are substring searches. In other words, this:

s = "This be a string"
if s.find("is") == -1:
    print "No 'is' here!"
else:
    print "Found 'is' in the string."

It would print Found 'is' in the string. Similarly, if "is" in s: would evaluate to True. This may or may not be what you want.

Answer 5

str.find() method

The second method is to use the str.find() method. Here, we call the .find() method on the string in which substring is to found. We pass the substring to the find() method and check its return value. If its value is other than -1, the substring was found in the string, otherwise not. The value returned is the index where substring was found.

>>> some_string = "valar morghulis"

>>> some_string.find("morghulis")
6

>>> some_string.find("dohaeris")
-1

Answer 6

You can simply use a if statement like you do for checking a condition.
Here also you can check if a substring is present in a string and if it is true continue with the remaining logic