The following code validates a number exactly equal to '2018'
Example
import re s = '2018' match = re.match(r'\b2018\b',s) print match.group()
Output
This gives the output
2018
Example
The following code validates any five digit positive integer
import re s = '2346' match = re.match(r'(?<!-)\b[1-9]\d{4}\b',s) print match s2 = '56789' match = re.match(r'(?<!-)\b[1-9]\d{4}\b',s2) print match.group()
Output
None 56789