add notes

README.md

@@ -1,4 +1,4 @@
-# DJFZ 2021
+# DJFZ 202/home/kuba/Syncthing/przedmioty/2021-01/djfz/djfz-2021/README.md1
 
 ## Zajęcia 1 11.10.2021
 
@@ -174,3 +174,134 @@ re.search('mam (kota).*(kota|psa)','Ja mam kota. Ala ma psa.').group(1)
 
 re.search('mam (kota).*(kota|psa)','Ja mam kota. Ala ma psa.').group(2)
 ```
+
+
+
+
+
+
+
+### Przykłady wyrażenia regularne 2 (objaśnienia na laboratoriach)
+
+####  ^
+```
+re.search('[^0-9][0-9]+[^0-9]', '123-456-789')
+```
+
+#### cudzysłów
+'' oraz "" - oznaczają to samo w pythonie
+
+' ala ma psa o imieniu "Burek"'
+" ala ma psa o imieniu 'Burek'"
+
+' ala ma psa o imieniu \'Burek\''
+" ala ma psa o imieniu \"Burek\""
+
+#### multiline string
+
+#### raw string
+
+przy raw string znaki \ traktowane są jako zwykłe znaki '\'
+
+chociaż nawet w raw string nadal są escapowane (chociaż wtedy \ pozostają również w stringu bez zmian)
+
+https://docs.python.org/3/reference/lexical_analysis.html
+
+dobra praktyka - wszędzie escapować
+
+```
+'\\'
+print('\\')
+
+r'\\'
+print(r'\\')
+
+
+print("abcd")
+print("ab\cd")
+print(r"ab\cd")
+
+print("ab\nd")
+print(r"ab\nd")
+
+
+print("\"")
+print(r"\"")
+
+print("\")
+print(r"\")
+
+re.search('\\', r'a\bc')
+re.search(r'\\', r'a\bc')
+re.search('\\\\', r'a\bc')
+```
+
+#### RE SUB
+```
+re.sub(pattern, replacement, string)
+
+re.sub('a','b', 'ala ma kota')
+```
+
+#### backreferencje:
+
+```
+
+re.search(r' \d+ \d+', 'ala ma 41 41 kota')
+re.search(r' \d+ \d+', 'ala ma 41 123 kota')
+re.search(r' (\d+) \1', 'ala ma 41 41 kota')
+re.search(r' (\d+) \1', 'ala ma 41 123 kota')
+```
+
+#### lookahead ( to sa takie assercje):
+```
+re.search(r'ma kot', 'ala ma kot')
+re.search(r'ma kot(?=[ay])', 'ala ma kot')
+re.search(r'ma kot(?=[ay])', 'ala ma kotka')
+re.search(r'ma kot(?=[ay])', 'ala ma koty')
+re.search(r'ma kot(?=[ay])', 'ala ma kota')
+
+re.search(r'ma kot(?![ay])', 'ala ma kot')
+re.search(r'ma kot(?![ay])', 'ala ma kotka')
+re.search(r'ma kot(?![ay])', 'ala ma koty')
+re.search(r'ma kot(?![ay])', 'ala ma kota')
+```
+
+#### named groups
+```
+r = re.search(r'ma (?P<ilepsow>\d+) kotow i (?P<ilekotow>\d+) psow', 'ala ma 100 kotow i 200 psow')
+r.groups()
+r.groups('ilepsow')
+r.groups('ilekotow')
+```
+
+#### re.split
+```
+('a,b,c,d').split(',')
+re.split(r',', 'a,b,c,d') 
+re.split(r'[.,]', 'a,b.c,d') 
+```
+#### \w word character
+```
+\w - matchuje Unicod word character , jeżeli flaga ASCII to [a-zA-Z0-9_]
+\w - odwrotne do \W, jezeli flaga ASCI to [^a-zA-Z0-9_]
+
+re.findall(r'\w+', 'ala ma 3 koty')
+re.findall(r'\W+', 'ala ma 3 koty')
+```
+#### początek albo koniec słowa | word boundary
+```
+re.search(r'\bkot\b', 'Ala ma kota')
+re.search(r'\bkot\b', 'Ala ma kot')
+re.search(r'\bkot\b', 'Ala ma kot.')
+re.search(r'\bkot\b', 'Ala ma kot ')
+
+re.search(r'\Bot\B', 'Ala ma kot ')
+re.search(r'\Bot\B', 'Ala ma kota ')
+```
+#### MULTILINE
+```
+re.findall(r'^Ma', 'Ma kota Ala\nMa psa Jacek') 
+re.findall(r'^Ma', 'Ma kota Ala\nMa psa Jacek', re.MULTILINE)
+```
+#### RE.COMPILE

compile_example.py

@@ -0,0 +1,64 @@
+# fron https://stackoverflow.com/questions/452104/is-it-worth-using-pythons-re-compile#comment108948583_452104
+
+import re
+import time
+
+def setup(N=1000):
+    # Patterns 'a.*a', 'a.*b', ..., 'z.*z'
+    patterns = [chr(i) + '.*' + chr(j)
+                    for i in range(ord('a'), ord('z') + 1)
+                    for j in range(ord('a'), ord('z') + 1)]
+    # If this assertion below fails, just add more (distinct) patterns.
+    # assert(re._MAXCACHE < len(patterns))
+    # N strings. Increase N for larger effect.
+    strings = ['abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz'] * N
+    return (patterns, strings)
+
+def without_compile():
+    print('Without re.compile:')
+    patterns, strings = setup()
+    print('searching')
+    count = 0
+    for s in strings:
+        for pat in patterns:
+            count += bool(re.search(pat, s))
+    return count
+
+def without_compile_cache_friendly():
+    print('Without re.compile, cache-friendly order:')
+    patterns, strings = setup()
+    print('searching')
+    count = 0
+    for pat in patterns:
+        for s in strings:
+            count += bool(re.search(pat, s))
+    return count
+
+def with_compile():
+    print('With re.compile:')
+    patterns, strings = setup()
+    print('compiling')
+    compiled = [re.compile(pattern) for pattern in patterns]
+    print('searching')
+    count = 0
+    for s in strings:
+        for regex in compiled:
+            count += bool(regex.search(s))
+    return count
+
+start = time.time()
+print(with_compile())
+d1 = time.time() - start
+print(f'-- That took {d1:.2f} seconds.\n')
+
+start = time.time()
+print(without_compile_cache_friendly())
+d2 = time.time() - start
+print(f'-- That took {d2:.2f} seconds.\n')
+
+start = time.time()
+print(without_compile())
+d3 = time.time() - start
+print(f'-- That took {d3:.2f} seconds.\n')
+
+print(f'Ratio: {d3/d1:.2f}')