python - IndexError：列表索引超出范围，对列表求和

Question

我只是不想计算总和Ic[n][0 until 12]并将其保存在 nw = list() 中，但是......它不起作用。我收到一个错误，告诉我"list index is out of range". 我现在不知道如何解决它。她是代码：

    for n in range(0, 12):
        for r in range(0, 12):
            nw[n] += Ic[n][r]
    print nw

以下是中的值

Ic = [[-0.058763399720191956, -0.42418426275253296, -0.1281072050333023, 0.15460245311260223, -0.05813126266002655, -0.09746139496564865, 0.013134755194187164, 0.49814605712890625, -0.14812283217906952, 0.10285533964633942, 0.11999548971652985, 0.39407849311828613, -0.004134092479944229, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan], [2.5735421180725098, 2.1772024631500244, 0.28750336170196533, 0.02845955640077591, -0.5908316373825073, -0.7313328981399536, -0.5317823886871338, 0.19332526624202728, -0.7856833338737488, -0.38039201498031616, -0.4801616072654724, -0.2276214212179184, -0.5854479670524597, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan], [..]] 

上述结构重复50次。

Answer 1

我猜你已经定义nw=[]了，然后你试图分配nw[0] = 123. 这将引发错误。尝试 ：

nw =[sum(x[:12]) for x in Ic[:12]]