flatten list in python

Question

I want to flatten the list:

exampleArray = [[[151.68694121866872]], 
                [[101.59534468349297]], 
                [[72.16055999176308]]]

to:

[151.68694121866872, 101.59534468349297, 72.16055999176308]

Right now I am doing this:

resultArray= list(chain.from_iterable(list(chain.from_iterable(exampleArray))))

Even though it works I wanted to know if there's a better way.

Answer 1

怎么样

result = [x[0][0] for x in exampleArray]

Answer 2

In [6]: from itertools import chain

In [7]: lis=[[[151.68694121866872]], [[101.59534468349297]], [[72.16055999176308]]]

In [8]: list(chain(*(chain(*lis))))

Out[8]: [151.68694121866872, 101.59534468349297, 72.16055999176308]

Answer 3

There isn't a better way, this is the most recommended way. See official recipes

def flatten(listOfLists):
    "Flatten one level of nesting"
    return chain.from_iterable(listOfLists)

Answer 4

You don't need to convert the itertools.chain object (an iterable) into a list:

resultArray= list(chain.from_iterable(list(chain.from_iterable(exampleArray))))
# could be rewritten as
resultArray= list(chain.from_iterable(chain.from_iterable(exampleArray)))

.

You could write a deepness function using recursion:

def deep_chain_from_iterable(it, n):
    if n == 0:
        return list(it)
    else:
        return deep_chain_from_iterable(itertools.chain.from_iterable(it),n-1)

deep_chain_from_iterable(exampleArray, 2)

Answer 5

对于固定深度（如示例），您可以求和足够的次数：

sum(sum(listoflistsoflists, []), [])