Python 使用 lambda 函数在嵌套列表中查找总和
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Finding a sum in nested list using a lambda function
提问by hlin117
I have a data structure similar to this
我有一个与此类似的数据结构
table = [
("marley", "5"),
("bob", "99"),
("another name", "3")
]
What I would like to do, to get the sum of the 2nd column (5 + 99 + 3) functionally like this:
我想要做什么，在功能上像这样获得第二列 (5 + 99 + 3) 的总和：
total = sum(table, lambda tup : int(tup[1]))
That would be similar syntax to the python function sorted, but that's not how you would use python's sumfunction.
这与 python function 的语法相似sorted，但这不是您使用 pythonsum函数的方式。
What's the pythonic/functional way to sum up the second column?
总结第二列的 pythonic/function 方法是什么？
采纳答案by Peter de Rivaz
回答by Joran Beasley
sum(map(int,zip(*table)[-1]))
is one way to do it ... there are many options however
是一种方法......但是有很多选择
回答by rth
reduce can help
减少可以帮助
total = reduce(lambda x,y:x+int(y[1]), table,0)
回答by FredrikHedman
If you want to use lambda the following should solve it:
如果你想使用 lambda，以下应该解决它：
total = sum(map(lambda x: int(x[1]), table))
回答by Peter Wood
You can also get at the values in a dictionary:
您还可以获取字典中的值：
total = sum(map(int, dict(table).values())
This may be a little obscure.
这可能有点晦涩。
回答by SRG
One way is using indexing.
一种方法是使用索引。
total=sum(items[1] for items in table)
