How can I use list comprehension for this case:
>>> a = 'A'
>>> lista = [1, 2, 8, 5, 10]
>>> l = [a, num for num in lista if num%2 == 0]
File "<stdin>", line 1
l = [a, num for num in lista if num%2 == 0]
^
SyntaxError: invalid syntax
As you can see this syntax is not possible. My idea was to create a new list only with the even numbers of lista and a .
['A', 2, 8, 10]
How can I do this with list comprehension ?
(as @stderr concurrently suggested), in this case the simplest is to concatenate (or + ) the "a" to the list in understanding
novalista = [a] + [num for num in lista if num%2 == 0]
To verify that the current iteration item is an integer , and an even number or equal a do:
l = [item for item in lista if type(item) is int and item % 2 == 0 or item == a]
See an example:
lista = [1, 2, 8, 5, 10, 'A', 'b', 12]
a = 'A'
print([item for item in lista if type(item) is int and item % 2 == 0 or item == a])
# [2, 8, 10, 'A', 12]
Editing : If it is a list that has only numbers and you just want to add a , such as suggested by JJoão , concatenate the variable as a list:
l = [item for item in lista if item % 2 == 0] + [a]
In addition to the module operator % , you can also use the bitwise and , for example: item & 1 == 0 .