String letterali formattate

Espressioni regolari in Python

Maria Eugenia Inzaugarat

Data Scientist

f-string

  • Sintassi minima
  • Aggiungi il prefisso f alla stringa

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
Espressioni regolari in Python

Conversione di tipo

  • Conversioni consentite:
    • !s (versione stringa)
    • !r (rappresentazione stampabile, cioè con virgolette)
    • !a (come !r ma fa l'escape dei caratteri 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
Espressioni regolari in Python

Specificatori di formato

  • Specificatori di formato standard:
    • e (notazione scientifica, es. 5 10^3)
    • d (cifra, es. 4)
    • f (float, es. 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!
Espressioni regolari in Python

Specificatori di formato

 

  • 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
Espressioni regolari in Python

Accessi per indice

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

 

  • Usa le virgolette per gli accessi per indice: family["dad"]
print(f"Is your dad called {family[dad]}?")
NameError: name 'dad' is not defined
Espressioni regolari in Python

Sequenze di escape

  • Sequenze di escape: backslash \
print("My dad is called "John"")
SyntaxError: invalid syntax

 

my_string = "My dad is called \"John\""
My dad is called "John"
Espressioni regolari in Python

Sequenze di escape

family = {"dad": "John", "siblings": "Peter"}
  • Backslash non consentiti nelle f-string
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?
Espressioni regolari in Python

Operazioni inline

  • Vantaggio: valuta espressioni e chiama funzioni inline
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
Espressioni regolari in Python

Chiamare funzioni

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
Espressioni regolari in Python

Vamos praticar!

Espressioni regolari in Python

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