计算嵌套列表中的元素答案

【问题标题】：Count elements in nested list计算嵌套列表中的元素
【发布时间】：2013-09-11 18:38:06
【问题描述】：

下面的python代码应该清楚我想要完成什么。

# Say I have the following list and I want to keep count of 1's while going through each nested list
L = [[1,1,0,0,0,1],[1,1,0,0,0,0],[0,0,0,0,0,1],[1,1,1,1,1,1]]

# So I'd like to get a list containing [3, 5, 6, 12]
# I tried to find a compact way of doing this by mapping this list into a another list like such 
T = [L[:i].count(1) for i in range(len(L))]
# >>> [0, 0, 0, 0]


# But this doesn't work so how to count occurances for nested lists?
# Is there a compact way of doing this (maybe with Lambda functions)?

# I'd like to avoid using a function like:
def Nested_Count():
    Result = []
    count = 0
    for i in L:
        count += i.count(1)
        Result.append(count)
    return Result
# >>> [3, 5, 6, 12]

请让我知道是否可以使用更紧凑的代码来执行此操作。

谢谢！

【问题讨论】：

标签： python list count mapping nested

【解决方案1】：

[sum([x.count(1) for x in L[:i]]) for i in range(1, len(L) + 1)]

应该做你想做的。

【讨论】：

【解决方案2】：

使用sum 和列表理解。

L = [[1,1,0,0,0,1],[1,1,0,0,0,0],[0,0,0,0,0,1],[1,1,1,1,1,1]]
L2 = [sum(x) for x in L]
T = [sum(L2[:x+1]) for x in xrange(len(L2))]

【讨论】：