Différences

Ci-dessous, les différences entre deux révisions de la page.

--- teaching:progappchim:notions_fondamentales [2021/01/11 12:01] – [Le type de données texte ou "string" :] villersd
+++ teaching:progappchim:notions_fondamentales [2021/01/25 11:57] – [Le type de données texte ou "string" :] villersd
@@ Ligne 91: / Ligne 91: @@
 //Cf.// [[http://www.courspython.com/boucles.html|cet autre cours]] avec des illustrations et des exemples de code exécutable sur le site [[http://www.pythontutor.com|pythontutor]].
+FIXME : ajouter d'autres possibilités telles que présentées dans [[https://medium.com/analytics-vidhya/looping-techniques-in-python-3bbf907b8dfa|Looping Techniques in Python - Let’s learn about looping techniques using functions like enumerate, zip, sorted, reversed in python]] Indhumathy Chelliah; Medium, 30/07/2020
 ----
@@ Ligne 124: / Ligne 126: @@
   * Conversion en nombre (donnée numérique créée à partir d'une chaîne de caractères) : int("587"), float("3.14")
   * Pour la concaténation d'une liste de chaîne, la fonction join est plus adaptée que "+" (cf. [[https://towardsdatascience.com/do-not-use-to-join-strings-in-python-f89908307273|ici]]) :
-<code>
+<code python>
 strings = ['A', 'bac', 'cali', 'jkppl']
 text = ''.join(strings)
@@ Ligne 145: / Ligne 147: @@
 string.printable # = digits + ascii_letters + punctuation + whitespace
 </code>
+=== Modifications, recherches, index, vérifications,... ===
+<code python>
+s.capitalize() # captilizes (first character becomes uppercase) the string
+s.lower() # all characters become lowercase
+s.casefold() # more rigorous lowercase (languages other than English are covered)
+s.upper() # all characters become uppercase
+s.count(sub) # count occurences of substring sub in s
+s.count(sub, start) # count occurences of substring sub starting from start position in string s
+s.count(sub, start, end) # count occurences of substring sub from start to end — 1 position in string s
+s.find(sub) # returns index of first occurence of substring sub in s, return -1 if not found
+s.find(sub, start) # returns index of first occurence of substring sub starting from start position in string s, returns -1 if not found
+s.find(sub, start, end) # returns index of first occurence of substring sub from start to end — 1 position in string s, return -1 if not found
+s.index(sub) # returns index of first occurence of substring sub in s, raises error if not found
+s.index(sub, start) # returns index of first occurence of substring sub starting from start position in string s, raises error if not found
+s.index(sub, start, end) # returns index of first occurence of substring sub from start to end — 1 position in string s, raises error if not found
+len(str) # returns length of string
+s.startswith(prefix) # checks if s starts with prefix
+s.startswith(prefix, start) # checks if s starts with prefix starting from start position
+s.startswith(prefix, start, end) # checks if s starts with prefix starting from start position until end — 1 position
+s.endswith(suffix) # checks if s ends with suffix
+s.endswith(suffix, start) # checks if s ends with suffix starting from start position
+s.endswith(suffix, start, end) # checks if s ends with suffix starting from start position until end — 1 position
+s.isalnum() # checks if string is alphanumeric
+s.isalpha() # checks if string contains only alphabets
+s.isnumeric() # checks if string contains only numbers
+s.islower() # checks if all alphabets in string s are lowercase
+s.isupper() # checks if all alphabets in string s are uppercase
+s.isspace() # checks if s is a space character
+s.replace(old, new) # replaces substring old with substring new
+s.replace(old, new, count) # replace substring old with substring new for count number of times starting from left side of string s
+s.ljust(width) # puts width — len(s) spaces on the right side of string s
+s.ljust(width, fillchar=c) # puts character c width — len(s) times on the right side of string s
+s.rjust(width) # puts width — len(s) spaces on the left side of string s
+s.rjust(width, fillchar=c) # puts character c width — len(s) times on the left side of string s
+s.strip() # all spaces gone left and right both sides of string s
+s.lstrip() # all spaces gone on left side of string s
+s.rstrip() # all spaces gone on right side of string s
+s.strip(k) # all substrings k gone left and right both sides of string s
+s.lstrip(k) # all substrings k gone on left side of string s
+s.rstrip(k) # all substrings k gone on right side of string s
+s.split(‘,’) # splits the string by ‘,’; returns a list
+s.split(‘::’) # splits the string by ‘::’; returns a list
+s.split(‘ ‘) # splits the string by ‘ ‘; returns a list
+s.zfill(width) # adds width — len(s) zeros on the left side; if a +/- sign is there then zeros are added after it
+s.join(l) # joins a list or string l with substring s
+</code>
+=== Applications à la détection de palindromes et anagrammes ===
+<code python string-palindrome-01.py>
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Created on Mon Jan 25 10:58:37 2021
+@author: villersd
+Un palindrome est un texte ou une séquence plus générale (notes de musique,
+code génétique,...), dont l'ordre des lettres (ou des notes,...) reste le même
+qu'on le lise de gauche à droite ou de droite à gauche.
+Source : https://fr.wikipedia.org/wiki/Palindrome
+"""
+import unicodedata
+def palindrome(string_to_check):
+    if string_to_check.lower().replace(' ', '') == string_to_check.lower().replace(' ', '')[::-1]:
+        return True
+    else:
+        return False
+def remove_accents(input_str):
+    """
+    Les lettres accentuées viennent compliquer le problème...
+    cf. https://stackoverflow.com/questions/517923/what-is-the-best-way-to-remove-accents-normalize-in-a-python-unicode-string
+    """
+    nfkd_form = unicodedata.normalize('NFKD', input_str)
+    return u"".join([c for c in nfkd_form if not unicodedata.combining(c)])
+string0 = 'Esope reste ici et se repose'
+print(string0, palindrome(string0))
+string1 = 'Ésope reste ici et se repose'
+print(string1, palindrome(string1))
+print(string1, remove_accents(string1), palindrome(remove_accents(string1)))
+</code>
+<code python string-anagramme-00.py>
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Created on Mon Jan 25 11:42:18 2021
+@author: villersd
+Une anagramme est un mot ou une expression obtenu en permutant les lettres
+d'un mot ou d'une expression de départ
+Source : https://fr.wikipedia.org/wiki/Anagramme
+"""
+string1 = 'manoir'
+string2 = 'romain'
+print(string1, sorted(string1))
+print(string2, sorted(string2))
+# exercice : utiliser cette fonction sorted() et appliquer les transformations
+# de la fonction de vérification de palindromes pour détecter une anagramme.
+</code>
 === Références ===
@@ Ligne 281: / Ligne 401: @@
-Consulter la [[https://docs.python.org/2/library/collections.html|documentation officielle]], et ces liens ([[http://pymbook.readthedocs.org/en/latest/collections.html|1]], [[https://pymotw.com/2/collections/counter.html|2]], [[https://dzone.com/articles/python-201-whats-a-deque|3]], [[https://towardsdatascience.com/the-most-undervalued-standard-python-library-14021632f692|4]])
+  * Consulter la [[https://docs.python.org/2/library/collections.html|documentation officielle]], et ces liens :
+    * [[http://pymbook.readthedocs.org/en/latest/collections.html]]
+    * [[https://pymotw.com/2/collections/counter.html]
+    * [[https://dzone.com/articles/python-201-whats-a-deque|Python 201: What’s a Deque?]]
+    * [[https://towardsdatascience.com/the-most-undervalued-standard-python-library-14021632f692|The Most Undervalued Standard Python Library Collections for data scientists]] Tyler Folkman, Medium, Oct 26, 2019 (video)
+    * [[https://levelup.gitconnected.com/introducing-high-performance-datatypes-in-python-with-the-collections-library-3d8c334827a5|Introducing high-performance datatypes in Python with the collections library]] George Seif, Medium, Oct 15, 2019
 Des types non intégrés par défaut dans Python peuvent facilement être implémentés, en utilisant les types répandus. C'est pas exemple le cas des [[https://fr.wikipedia.org/wiki/Arbre_enracin%C3%A9|arbres]] (informatique, théorie des graphes) :
@@ Ligne 584: / Ligne 709: @@
   * Pour en savoir plus, consultez la page [[https://docs.python.org/2/tutorial/inputoutput.html#reading-and-writing-files]].
   * [[https://medium.com/better-programming/a-cheat-sheet-on-reading-and-writing-files-in-python-e78297adf413|A Cheat Sheet on Reading and Writing Files in Python - Quick reference on how to read and write files]] Yong Cui, Medium, 13/01/2020
+  * [[https://medium.com/techtofreedom/file-handling-in-python-daee4586a64|File Handling in Python]] Yang Zhou, Medium, 25/04/2020