Name

in

Examples

# Check if a given substring is present in a string
message = "Now is the winter of our discontent."
print("winter" in message) # Prints 'True'

# Check if an item is present in a list
data = [17, 24, 32, 912, 403]
print(17 in data) # Prints 'True'

# Check if a key is present in a dictionary
elements = {'H': 'hydrogen', 'He': 'helium', 'Li': 'lithium'}
print('He' in elements) # Prints 'True'

# Note: The "in" operator doesn't check for *values* in dictionaries!
print('hydrogen' in elements) # Prints 'False'

Description Returns True if a given value is in a string, list or dictionary, and False otherwise.

The in operator works slightly differently for different types. When used with strings, it checks if a substring is found within another string. When used with lists or tuples, it checks if a given value is found inside the list or tuple. When used with dictionaries, it checks to see if a particular key is present in the dictionary.

(Note that the use of the keyword in as an operator is separate from and unrelated to its use in the syntax of for loops and list comprehensions.)
Syntax
	item in object
Parameters
iThe item whose presence to check for.
aThe object (e.g., string, list, dictionary) to search inside.
Related list()
string
Dictionary
Updated on Tue Jul 11 06:52:23 2017.
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