python - Convert part of string type in multidimensional list to integer type

Question

shell.txt
a1 b1 0.2 0
a1 c1 0.8 0
b1 c1 0.7 0
a2 b2 1 0
a2 d2 0.4 0
d2 b2 0.6 0
a1 a2 1 1
a2 a1 0.1 1
b1 b2 0.5 1
b2 b1 0 1

with open('shell.txt') as f:
    lines = f.readlines()
mylist = [line.strip().split() for line in lines]

Since the txt data is all string type after loading, now we need to convert the last two columns into integer types. Please give me some clean methods, thank you

Answer 1

result = []
for i in f:
    s = i.split()
    result.append(s[:-2]+map(lambda x: int(float(x)), ss[-2:]))
print result