Chaînes littérales formatées

Expressions régulières en Python

Maria Eugenia Inzaugarat

Data Scientist

f-strings

  • Syntaxe minimale
  • Ajouter le préfixe f à la chaîne

way = "code"
method = "learning Python faster"
print(f"Practicing how to {way} is the best method for {method}")
Practicing how to code is the best method for learning Python faster
Expressions régulières en Python

Conversion de type

  • Conversions permises :
    • !s (version chaîne)
    • !r (représentation imprimable, avec guillemets)
    • !a (comme !r, mais échappe les caractères non ASCII)

 

name = "Python"

print(f"Python is called {name!r} due to a comedy series")
Python is called 'Python' due to a comedy series
Expressions régulières en Python

Indicateurs de format

  • Indicateurs de format standard :
    • e (notation scientifique, p. ex. 5 10^3)
    • d (entier, p. ex. 4)
    • f (flottant, p. ex. 4.5353)

 

number = 90.41890417471841

print(f"In the last 2 years, {number:.2f}% of the data was produced worldwide!")
In the last 2 years, 90.42% of the data was produced worldwide!
Expressions régulières en Python

Indicateurs de format

 

  • datetime

 

from datetime import datetime
my_today = datetime.now()
print(f"Today's date is {my_today:%B %d, %Y}")
Today's date is April 14, 2019
Expressions régulières en Python

Recherches par index

family = {"dad": "John", "siblings": "Peter"}
print("Is your dad called {family[dad]}?".format(family=family))
Is your dad called John?

 

  • Utilisez des guillemets pour l'indexation : family["dad"]
print(f"Is your dad called {family[dad]}?")
NameError: name 'dad' is not defined
Expressions régulières en Python

Séquences d'échappement

  • Séquences d'échappement : barres obliques inverses \
print("My dad is called "John"")
SyntaxError: invalid syntax

 

my_string = "My dad is called \"John\""
My dad is called "John"
Expressions régulières en Python

Séquences d'échappement

family = {"dad": "John", "siblings": "Peter"}
  • Les barres obliques inverses ne sont pas permises dans les f-strings
print(f"Is your dad called {family[\"dad\"]}?")
SyntaxError: f-string expression part cannot include a backslash

 

print(f"Is your dad called {family['dad']}?")
Is your dad called John?
Expressions régulières en Python

Opérations en ligne

  • Avantage : évaluer des expressions et appeler des fonctions en ligne
my_number = 4
my_multiplier = 7
print(f'{my_number} multiplied by {my_multiplier} is {my_number * my_multiplier}')
4 multiplied by 7 is 28
Expressions régulières en Python

Appeler des fonctions

def my_function(a, b):
  return a + b
print(f"If you sum up 10 and 20 the result is {my_function(10, 20)}")
If you sum up 10 and 20 the result is 30
Expressions régulières en Python

Passons à la pratique !

Expressions régulières en Python

Preparing Video For Download...