Dada una lista, la tarea es eliminar los valores finales de Ninguno del último de la lista. Analicemos algunos métodos para resolver la tarea dada.
Ejemplos:
Input: [1, 2, 3, 4, None, 76, None, None] Output: [1, 2, 3, 4, None, 76] Input: [1, 2, None, None, None, None, None, 5] Output: [1, 2, None, None, None, None, None, 5]
Método #1: Usar un método ingenuo
# Python code to demonstrate
# to remove trailing None
# elements from lists
# initialising lists
ini_list = [1, 2, 3, 4, None, 76, None, None, None]
# printing initial dictionary
print ("initial dictionary", str(ini_list))
# code toremove trailing None values
# from lists
while not ini_list[-1]:
ini_list.pop()
# printing result
print ("resultant list", str(ini_list))
Producción:
initial dictionary [1, 2, 3, 4, None, 76, None, None, None] resultant list [1, 2, 3, 4, None, 76]
Método #2: Usaritertools.dropwhile()
# Python code to demonstrate
# to remove trailing None
# elements from lists
from itertools import dropwhile
# initialising lists
ini_list = [1, 2, 3, 4, None, 76, None, None, None]
# printing initial dictionary
print ("initial dictionary", str(ini_list))
# code toremove trailing None values
# from lists
res = list(reversed(tuple(dropwhile(lambda x: x is None,
reversed(ini_list)))))
# printing result
print ("resultant list", str(res))
Producción:
initial dictionary [1, 2, 3, 4, None, 76, None, None, None] resultant list [1, 2, 3, 4, None, 76]
Método #3: Usaritertools.takewhile()
# Python code to demonstrate
# to remove trailing None
# elements from lists
from itertools import takewhile
# initialising lists
ini_list = [1, 2, 3, 4, None, 76, None, None, None]
# printing initial dictionary
print ("initial dictionary", str(ini_list))
# code toremove trailing None values
# from lists
res = ini_list[:-len(list(takewhile(lambda x: x == None,
reversed(ini_list))))]
# printing result
print ("resultant list", str(res))
Producción:
initial dictionary [1, 2, 3, 4, None, 76, None, None, None] resultant list [1, 2, 3, 4, None, 76]
Método n.° 4: usar la comprensión de enumeración y lista
# Python code to demonstrate
# to remove trailing None
# elements from lists
# initialising lists
ini_list = [1, 2, 3, 4, None, 76, None, None, None]
# printing initial dictionary
print ("initial dictionary", str(ini_list))
# code toremove trailing None values
# from lists
res = [x for n, x in enumerate(ini_list)
if any(y is not None for y in ini_list[n:])]
# printing result
print ("resultant list", str(res))
Producción:
initial dictionary [1, 2, 3, 4, None, 76, None, None, None] resultant list [1, 2, 3, 4, None, 76]
Publicación traducida automáticamente
Artículo escrito por garg_ak0109 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA