match() in python

re.match(pattern, string):

• This method finds match if it occurs at start of the string.
• re.match(pattern, string, flags=0)

flags:

• Represent properties or rules to follow while matching the pattern.
• We can specify different flags using bitwise OR (|)
• On success match() function returns match object.
• On failure, it returns None.
• We use group() or groups() function of match object to get matched expression.

import re
line = "python online session"

res = re.match(r'java' , line)
print("Failure : ", res)

res = re.match(r'python' , line)
print("Success : ", res)

Note: ‘r’ is representing ‘raw input’.  It is looking into input raw String for specified pattern.

Match object:

• The object which is returned by the function if match found
• Span() : return a tuple containing the start and end positions of match
• .string : returns the string passed into that function
• group() : returns the part of the string where there is a match

import re
line = "python online session"
res = re.match(r'python' , line)

print("Span : ", res.span())
print("String :", res.string)
print("Pattern :", res.group())

output:

Span :  (0, 6)
String : python online session
Pattern : python