a = [21, 2.5 , -23.2, 8.4, -4, 3, -1.03]
a = [21, 2.5 , -23.2, 8.4, -4, 3, -1.03]
#遍历列表
for i in range(len(a)):
if a[i]<0: #发现负数元素就取反
a[i] = -a[i]
print(a)
a = [21, 2.5 , -23.2, 8.4, -4, 3, -1.03]
b = [abs(i) for i in a]
print(b)
>>>[21, 2.5, 23.2, 8.4, 4, 3, 1.03]
可以使用abs()求绝对值函数