擅长:python、mysql、java
<p>您引用的是同一个列表<code>dem1</code>,这意味着当您附加值1000时,它将保留在您的列表<code>dem1</code>中,并且将来的附加值将建立此列表</p>
<p>试试这个:</p>
<pre><code>pdd = 1 # number of node i
r = 2 # number of commodity type c
e = 1 # number of period t
dem = []
dem2 = []
dem3 = []
for i in range(pdd):
for c in range(r):
dem1 = [] # create a new list
for t in range(e):
dem0 = 1000
dem1.append (dem0)
dem2.append (dem1)
dem.append(dem2)
print dem
</code></pre>