如何在Python中的for循环中添加空列表

Question

a=np.where(MACD[2]>0.)[0]
b=np.where(MACD[2]<0.)[0]
num=np.array([1,2])
num1=[]
for x in range (-1,-30,-1):
    while True:
       if(a[x]-a[x-1]>1):
          num1.append(num)
          print num1
          break

I want to append num but when I run it is hang over there. My desired output is num=[45,74,41,1,2] which mean the num1 will not be overwrite everytime it run while the for loop.

Answer 1

a=np.where(MACD[2]>0.)[0]
b=np.where(MACD[2]<0.)[0]

num=np.array([1])
num1=[]

for x in range (-1,-30,-1):#for MACD above  0
    if(a[x]-a[x-1]>1):
        num=a[x]
        num1.append(num)
        print num1

found out that additional num=a[x] will do