Multiple IF conditions in a python list comprehension
You can put you logic in a separate function, and then have the elegance of the list comprehension along with the readability of the function:
def cond(i):
if i % 4 == 0: return 'four'
elif i % 6 == 0: return 'six'
return i
l=[cond(i) for i in range(1,n)]
If you have lots of conditions, it is usually easier to maintain a single dict rather than a big if/else ladder:
def cond(i):
mkey={4:'four',6:'six'}
return next((mkey[k] for k in mkey if i%k == 0), i)
This uses the default version of next to find if any integer key is a multiple of that key or the number itself, the default, if not.
Which could be a single comprehension if desired:
[next((v for k,v in {4:'four',6:'six'}.items() if i%k==0), i) for i in range(1,10)]
How about
ar = [('four' if i % 4 == 0 else ('six' if i % 6 == 0 else i)) for i in range(1, n)]
For example, if n = 30
this is
[1, 2, 3, 'four', 5, 'six', 7, 'four', 9, 10, 11, 'four', 13, 14, 15, 'four', 17, 'six', 19, 'four', 21, 22, 23, 'four', 25, 26, 27, 'four', 29]
ETA: Here's how you could apply a list of conditions:
CONDITIONS = [(lambda i: i % 4 == 0, "four"), (lambda i: i % 6 == 0, "six"),
(lambda i: i % 7 == 0, "seven")]
def apply_conditions(i):
for condition, replacement in CONDITIONS:
if condition(i):
return replacement
return i
ar = map(apply_conditions, range(0, n))
ar = ["four" if i%4==0 else "six" if i%6==0 else i for i in range(1,30)]