Python startswith () function and endswith function, startswithendswith

Python startswith () function and endswith function, startswithendswith

Function: startswith ()

Purpose: Determine whether a string starts with a specified character or substring.

I. Function Description

Syntax: string. startswith (str, beg = 0, end = len (string ))
Or string [beg: end]. startswith (str)

Parameter description:

String: the string to be detected.
Str: the specified character or substring. (You can use tuples to match them one by one)
Beg: Set the start position of string detection (optional)
End: set the end position of string detection (optional)

If the beg and end parameters exist, check in the specified range; otherwise, check in the entire string.

Return Value

If a string is detected, True is returned; otherwise, False is returned. The default null character is True.

Function parsing: If the string starts with str, True is returned; otherwise, False is returned.

Ii. Instances

>>> S = 'Hello good boy doiido '>>> print s. startswith ('H') True >>> print s. startswith ('hel') True >>> print s. startswith ('h', 4) False >>> print s. startswith ('Go', 6, 8) True # match an empty Character Set >>> print s. startswith ('') True # matched tuples >>> print s. startswith ('T', 'B', 'H') True

Environment: used for if judgment

>>> if s.startswith('hel'):  print "you are right"else:  print "you are wrang"you are right 

Function: endswith ()

Function: determines whether a string ends with a specified character or substring. It is often used to determine the file type.

I. Function Description

Syntax: string. endswith (str, beg = [0, end = len (string)])
String [beg: end]. endswith (str)

Parameter description:

String: the string to be detected.
Str: specified character or substring (tuples can be used to match each character)
Beg: Set the start position of string detection (optional, starting from the left)
End: set the end position of string detection (optional, starting from the left)

If the beg and end parameters exist, check in the specified range; otherwise, check in the entire string.

Return Value:

If a string is detected, True is returned; otherwise, False is returned.

Resolution: If the string ends with str, True is returned; otherwise, False is returned.

Note: NULL characters are considered true.

Ii. Instances

>>> S = 'Hello good boy doiido '>>> print s. endswith ('O') True >>> print s. endswith ('id') True >>> print s. endswith ('Do ', 4) True >>> print s. endswith ('Do ',) False # match NULL Character Set >>> print s. endswith ('') True # match tuples >>> print s. endswith ('T', 'B', 'O') True

Common Environment: used to determine the file type (comparison, executable files)

>>> f = 'pic.jpg' >>> if f.endswith(('.gif','.jpg','.png')):  print '%s is a pic' %f else:  print '%s is not a pic' %f   pic.jpg is a pic 

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