简单列表划分问题 [英] Simple List division problem

问题描述

如何将列表分成一组子列表 - 如果列表是

不能均匀分割？

考虑这个例子：


x = [1,2,3,4,5,6,7,8,9,10]

y = 3＃我要打破的列表数x进入

z = y / x

我想得到的是3个子列表


print z [0] = [1 ，2,3]

print z [2] = [4,5,6]

print z [3] = [7,8,9,10]


显然不是偶数，一个列表将有4个元素，另外2个将b / b
具有3.，

最重要的逻辑，就是我会获得3个列表并找到一种方法来使用
python来尝试均匀地打破它，如果没有一个列表可以有更大的元素

我会使用itertools吗？我该怎么做？


谢谢

解决方案

marcstuart写道：

如果列表是

不能均匀分割，我如何将列表分成一组子列表？

考虑这个例子：


x = [1,2,3,4,5,6,7,8,9,10]

y = 3＃number of列表我想打破x进入

z = y / x


我想得到的是3个子列表


print z [0] = [1,2,3]

print z [2] = [4,5,6]

print z [3] = [7,8,9,10]


显然不是偶数，一个列表将有4个元素，另外2个将b / b
。最重要的逻辑是，我将获得3个列表，并找到一种方法来使用
python尝试均匀地破解它，如果不是一个列表可以有更大的

元素数量


我会使用itertools吗？我该怎么做？


谢谢

计算正常子列表的大小，以及额外的

与最后一个子列表一致。

然后提取y-1正常大小的子列表和一个可能更大的子列表。

>> x = [1,2,3,4,5,6,7,8,9,10]
y = 3
s = len（x）/ y
s＃正常子列表的大小

3

个;> E = LEN（X） - Ÿ* S＃为最后子列表多余的元素
E
'/ BLOCKQUOTE>

1个

>> z = [x [s * i：s * i + s] for i in range（y-1）] + [x [-se：]] #extract y-1

正常+ 1个较大的子列表

>> z

[[1,2,3]，[4,5,6] ，[7,8,9,10]]


完成！


加里赫伦

marcstuart写道：

如果列表是

不能均匀分割？考虑这个例子：


x = [1,2,3,4,5,6,7,8,9,10]

y = 3＃number列表我想打破x进入

z = y / x


我想得到的是3个子列表


打印z [0] = [1,2,3]

打印z [2] = [4,5,6]

打印z [3] = [7,8,9,10]


显然不是偶数，一个列表将有4个元素，另外2个将

有3.，

这里有一种方法：


＃砍掉它

n = len（x）/ y

z = [x [i：i + n] for x in xrange（0，len（x），n）]


＃如果最后一块太短，请将它添加到它之前

如果len（z [-1]）< n和len（z）1：

z [-2] .extend（z.pop（-1））


< / F>

1月12日，12：37 * pm，marcstuart< marc.stuart.ris ... @ gmail.comwrote：

如果列表是

不能均匀分割，我如何将列表分成一组子列表？

考虑这个例子：


x = [1,2,3,4,5,6,7,8,9,10]

y = 3 * * * ＃我要打破x的列表数量

z = y / x


我想得到的是3个子列表

print z [0] = [1,2,3]

print z [2] = [4,5,6]

print z [ 3] = [7,8,9,10]


显然不是偶数，一个列表将有4个元素，另外2个将b / b
有3个。 ，

最重要的逻辑，就是我将得到3个列表并找到一种方法来使用
python来尝试均匀地破坏它，如果不是一个列表可以有更大的

元素数量


我会使用iterto吗？ ols？我该怎么做？


谢谢

def list_split（x，y）：

dm = divmod（len（x），y​​）

如果dm [1]！= 0：

z = [x [i * y：i * y + y ] for x in xrange（len（x）/ y）if len（x [i * y：]）> = 2 * y]

z.append（x [（len（x） / y-1）* y：]）

else：

z = [x [i * y：i * y + y] for x in xrange（len（x） ）/ Y）]

返回ž

个;> ; list_split（[1,2,3,4,5,6,7,8,9,10]，3）

[[1,2,3]，[4,5,6]，[7,8,9,10]]

>> list_split（[1,2,3,4,5,6,7,8,9,10]，5）

[[1,2,3,4,5]，[6,7,8,9,10]]

>&g t; list_split（[1,2,3,4,5,6,7,8,9,10]，4）

[[1,2,3,4]，[5,6,7,8,9,10]]

>> list_split（[1,2,3,4,5,6,7,8,9,10]，2）

[[1,2]，[3,4]，[5,6]，[7,8]，[9,10]]

How do I divide a list into a set group of sublist''s- if the list is
not evenly dividable ?
consider this example:

x = [1,2,3,4,5,6,7,8,9,10]
y = 3 # number of lists I want to break x into
z = y/x
what I would like to get is 3 sublists

print z[0] = [1,2,3]
print z[2] = [4,5,6]
print z[3] = [7,8,9,10]

obviously not even, one list will have 4 elements, the other 2 will
have 3.,
the overriding logic, is that I will get 3 lists and find a way for
python to try to break it evenly, if not one list can have a greater
amount of elements

Would I use itertools ? How would I do this ?

Thanks

解决方案

marcstuart wrote:

How do I divide a list into a set group of sublist''s- if the list is
not evenly dividable ?
consider this example:

x = [1,2,3,4,5,6,7,8,9,10]
y = 3 # number of lists I want to break x into
z = y/x
what I would like to get is 3 sublists

print z[0] = [1,2,3]
print z[2] = [4,5,6]
print z[3] = [7,8,9,10]

obviously not even, one list will have 4 elements, the other 2 will
have 3.,
the overriding logic, is that I will get 3 lists and find a way for
python to try to break it evenly, if not one list can have a greater
amount of elements

Would I use itertools ? How would I do this ?

Thanks

Calculate the size of a normal sublist, and the amount of extra that
goes with the last sublist.
Then extract y-1 normal sized sublists and one possibly larger sublist.

>>x = [1,2,3,4,5,6,7,8,9,10]
y = 3
s = len(x)/y
s # size of normal sublists

3

>>e = len(x) - y*s # extra elements for last sublist
e

1

>>z = [x[s*i:s*i+s] for i in range(y-1)] + [x[-s-e:]] #extract y-1

normal + 1 larger sublists

>>z

[[1, 2, 3], [4, 5, 6], [7, 8, 9, 10]]

Done!

Gary Herron

marcstuart wrote:

How do I divide a list into a set group of sublist''s- if the list is
not evenly dividable ? consider this example:

x = [1,2,3,4,5,6,7,8,9,10]
y = 3 # number of lists I want to break x into
z = y/x

what I would like to get is 3 sublists

print z[0] = [1,2,3]
print z[2] = [4,5,6]
print z[3] = [7,8,9,10]

obviously not even, one list will have 4 elements, the other 2 will
have 3.,

here''s one way to do it:

# chop it up
n = len(x) / y
z = [x[i:i+n] for i in xrange(0, len(x), n)]

# if the last piece is too short, add it to one before it
if len(z[-1]) < n and len(z) 1:
z[-2].extend(z.pop(-1))

</F>

On Jan 12, 12:37*pm, marcstuart <[e-mail]:

How do I divide a list into a set group of sublist''s- if the list is
not evenly dividable ?
consider this example:

x = [1,2,3,4,5,6,7,8,9,10]
y = 3 * * *# number of lists I want to break x into
z = y/x

what I would like to get is 3 sublists

print z[0] = [1,2,3]
print z[2] = [4,5,6]
print z[3] = [7,8,9,10]

obviously not even, one list will have 4 elements, the other 2 will
have 3.,
the overriding logic, is that I will get 3 lists and find a way for
python to try to break it evenly, if not one list can have a greater
amount of elements

Would I use itertools ? How would I do this ?

Thanks

def list_split(x,y):
dm = divmod(len(x),y)
if dm[1] != 0:
z = [x[i*y:i*y+y] for i in xrange(len(x)/y) if len(x[i*y:])>=2*y]
z.append(x[(len(x)/y-1)*y:])
else:
z = [x[i*y:i*y+y] for i in xrange(len(x)/y)]
return z

>>list_split([1,2,3,4,5,6,7,8,9,10],3)

[[1, 2, 3], [4, 5, 6], [7, 8, 9, 10]]

>>list_split([1,2,3,4,5,6,7,8,9,10],5)

[[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]

>>list_split([1,2,3,4,5,6,7,8,9,10],4)

[[1, 2, 3, 4], [5, 6, 7, 8, 9, 10]]

>>list_split([1,2,3,4,5,6,7,8,9,10],2)

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

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