Regex or Regular Expressions:sequence of characters used to check whether a pattern exists in a given text or not. import re to be able to use it.
| Special Characters | Match |
|---|---|
| Period . | Single character except the newline |
| caret ^ | The start of the string |
| $ | The end of string |
| [abc] | a or b or c |
| [a-zA-Z0-9] | Any letter from (a to z) or (A to Z) or (0 to 9) |
| \ | Backslash |
| \w Lowercase 'w' | Matches any single letter, digit, or underscore |
| \W Uppercase 'W' | Matches any character not part of \w (lowercase w) |
| \s - Lowercase 's' | single whitespace character like: space, newline, tab, return |
| \S - Uppercase 'S' | Any character not part of \s (lowercase s) |
| \d - Lowercase d | decimal digit 0-9. |
| \D - Uppercase d | Any character that is not a decimal digit |
| \t - Lowercase t | Tab |
| \n - Lowercase n | Newline |
| \r - Lowercase r | Return |
| \A - Uppercase a | Only at the start of the string and it work across multiple lines as well |
| \Z - Uppercase z | at the end of the string |
| \b - Lowercase b | only the beginning or end of the word |
| Repetitions | Checks if |
|---|---|
| + | The character appears one or more times starting from that position |
| * | The character appears zero or more times starting from that position. |
| ? | The character appears exactly zero or one time starting from that position |
| {x} | Repeat exactly x number of times |
| {x,} | Repeat at least x times or more |
| {x, y} | Repeat at least x times but no more than y times |
import glob
import shutil
print('BEFORE:', glob.glob('shutil_copyfile.*'))
shutil.copyfile('shutil_copyfile.py', 'shutil_copyfile.py.copy')
print('AFTER:', glob.glob('shutil_copyfile.*'))
$ python3 shutil_copyfile.py
BEFORE: ['shutil_copyfile.py']
AFTER: ['shutil_copyfile.py', 'shutil_copyfile.py.copy']
refer to this to check the codes :https://pymotw.com/3/shutil/