Python String startswith() Function

The String startswith() method checks if a string starts with a specified prefix. It returns True if the string starts with the specified prefix, and False otherwise.

Syntax

my_string.startswith(prefix, start, end)

startswith() Parameters

Python String startswith() function parameters:

Parameter	Condition	Description
prefix	Required	Any string you want to search
start	Optional	An index specifying where to start the search. Default value is 0.
end	Optional	An index specifying where to stop the search. Default value is the end of the string.

startswith() Return Value

Python String startswith() function returns a boolean:

• True if a string starts with the specified suffix.
• False if a string does not start with the specified suffix.

Examples

Example 1: Check if a string starts with a given prefix

For example, let's check if the string starts with est:

my_str = 'Big, Bigger, Biggest'
prefix = 'Big'

result = my_str.startswith(prefix)
print(result) # Output: True

output

True

If the prefix does not appear as prefix of the given string, then startswith() method will return False:

my_str = "Big, Bigger, Biggest"
prefix = 'Aaa'

result = my_str.startswith(prefix)
print(result) # Output: False

output

False

Example 2: Check if a string starts with a given prefix with start and end indexes

If you want to limit the search to a substring of the given string, you can specify the start parameter and/or the end parameter.

my_str = 'Big, Bigger, Biggest'
prefix = "Big"

# startswith()
result = my_str.startswith(prefix)       
print(result) # Output: True

# startswith() after 4th index
result = my_str.startswith(prefix, 5)
print(result) # Output: True

# startswith() between 4th and 6th index
result = my_str.startswith(prefix, 4, 6) 
print(result) # Output: False

output

True
True
False

Example 3: Check if a string starts with a Tuple of possible prefixes

You can pass multiple prefixes to the startswith() method in the form of a Tuple. If the string starts with any item of the tuple, the method returns True, otherwise returns False.

my_str = 'Tom is a CEO'
prefixes = ('Tom','David','Anna')
result = my_str.startswith(prefixes)

print(result) # Output: True

output

True

my_str = 'Tom is a Dev'
prefixes = ('CFO','CEO','COO')
result = my_str.startswith(prefixes)

print(result) # Output: False

output

False

It works also with start and end parameters:

my_str = 'Tom is a CEO and a Dev'
prefixes = ('CFO','CEO','COO')

print(my_str[9:16]) # Output:  a CEO
result = my_str.startswith(prefixes, 9, 16)

print(result) # Output: True

output

CEO and
True