list = ["ABC", "DEF", ...]
k = 1
for i in list:
    if k = 1:
        print(i + "perviy print")
        k += 1
    else:
        print(i)

 print(i) for i in list

 [print(val + "perviy print") if i == 0 else print(val)  for i, val in enumerate(lst)]

  
>>> lst = [(i + 'x' if n == 0 else i) for n, i in enumerate(['abc', 'def', 'ghi'])]
>>> print(*lst, sep='\n')
abcx
def
ghi
>>>