将清单大致等份的最佳方法是什么?例如，如果列表有7个元素，并将其分为2部分，我们希望其中一部分有3个元素，而另一部分应该有4个元素。
我正在寻找类似even_split(L, n)的东西，它将L分解为n部分。
def chunks(L, n):
""" Yield successive n-sized chunks from L.
"""
for i in range(0, len(L), n):
yield L[i:i+n]
上面的代码给出了3个块，而不是3个块。我可以简单地转置(遍历这个，取每列的第一个元素，称之为第一部分，然后取第二个元素，把它放在第二部分，等等)，但这破坏了项目的顺序。
当前回答
假设你想分成5个部分:
p1, p2, p3, p4, p5 = np.split(df, 5)
其他回答
我尝试了大部分的解决方案，但它们并不适用于我的情况，所以我创建了一个新函数，适用于大多数情况和任何类型的数组:
import math
def chunkIt(seq, num):
seqLen = len(seq)
total_chunks = math.ceil(seqLen / num)
items_per_chunk = num
out = []
last = 0
while last < seqLen:
out.append(seq[last:(last + items_per_chunk)])
last += items_per_chunk
return out
舍入linspace并将其用作索引是一种比amit12690建议的更简单的解决方案。
function chunks=chunkit(array,num)
index = round(linspace(0,size(array,2),num+1));
chunks = cell(1,num);
for x = 1:num
chunks{x} = array(:,index(x)+1:index(x+1));
end
end
1>
import numpy as np
data # your array
total_length = len(data)
separate = 10
sub_array_size = total_length // separate
safe_separate = sub_array_size * separate
splited_lists = np.split(np.array(data[:safe_separate]), separate)
splited_lists[separate - 1] = np.concatenate(splited_lists[separate - 1],
np.array(data[safe_separate:total_length]))
splited_lists # your output
2>
splited_lists = np.array_split(np.array(data), separate)
使用列表推导式:
def divide_list_to_chunks(list_, n):
return [list_[start::n] for start in range(n)]
另一个简单可读的chunker的尝试。
def chunk(iterable, count): # returns a *generator* that divides `iterable` into `count` of contiguous chunks of similar size
assert count >= 1
return (iterable[int(_*len(iterable)/count+0.5):int((_+1)*len(iterable)/count+0.5)] for _ in range(count))
print("Chunk count: ", len(list( chunk(range(105),10))))
print("Chunks: ", list( chunk(range(105),10)))
print("Chunks: ", list(map(list,chunk(range(105),10))))
print("Chunk lengths:", list(map(len, chunk(range(105),10))))
print("Testing...")
for iterable_length in range(100):
for chunk_count in range(1,100):
chunks = list(chunk(range(iterable_length),chunk_count))
assert chunk_count == len(chunks)
assert iterable_length == sum(map(len,chunks))
assert all(map(lambda _:abs(len(_)-iterable_length/chunk_count)<=1,chunks))
print("Okay")
输出:
Chunk count: 10
Chunks: [range(0, 11), range(11, 21), range(21, 32), range(32, 42), range(42, 53), range(53, 63), range(63, 74), range(74, 84), range(84, 95), range(95, 105)]
Chunks: [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [11, 12, 13, 14, 15, 16, 17, 18, 19, 20], [21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31], [32, 33, 34, 35, 36, 37, 38, 39, 40, 41], [42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52], [53, 54, 55, 56, 57, 58, 59, 60, 61, 62], [63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73], [74, 75, 76, 77, 78, 79, 80, 81, 82, 83], [84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94], [95, 96, 97, 98, 99, 100, 101, 102, 103, 104]]
Chunk lengths: [11, 10, 11, 10, 11, 10, 11, 10, 11, 10]
Testing...
Okay
