将 list 中的元素分组并统计每组的个数

```
newlist = []
templist = []
num = len(mylist) // N
j = 0
for i in sorted(mylist):
if j % num == 0 and j != 0:
newlist.append(templist)
templist = []
if j % num < num:
templist.append(i)
j = j + 1

print(newlist)
```

alphatoad

2019-11-15 14:11:41 +08:00 via iPhone

O(n)

cherbim

2019-11-15 14:24:08 +08:00 via iPhone

先用 sorted 排序，然后一个 for 遍历……

arloor

2019-11-15 15:09:38 +08:00 via Android

java stream 可以做到不写 for

xiaolinjia

2019-11-15 16:29:31 +08:00

import math
a = [-10, -1.67, 1.74, 27.43, -3.4, -0.59, 13.01, 18.69, 0.68, -1.17, 2.96, 13.14, 12.76, -0.14, 12.76, 3, 3, 5, 7, -2, 20]

def function(temp: list, n):
step = math.ceil(len(temp)/n)
temp.sort()
s = slice(0, step)
for i in range(n):
print(temp[s])
s = slice(s.start + step, s.stop + step)

if __name__ == '__main__':
function(a, 6)

TimePPT

2019-11-15 21:54:41 +08:00

# 如果用 pandas 可以一个 for 都不用

import pandas as pd

lst = [-10, -1.67, 1.74, 27.43, -3.4, -0.59, 13.01, 18.69, 0.68, -1.17, 2.96, 13.14, 12.76, -0.14, 12.76, 3, 3, 5, 7, -2, 20]

n = 5

df_cut = pd.cut(lst, n)

df_cut.value_counts()

# pandas.cut 可以设置一系列函数确定均分区间的规则： https://pandas.pydata.org/pandas-docs/version/0.23.4/generated/pandas.cut.html

ladypxy

2019-11-17 20:13:34 +08:00

@TimePPT 感谢。请问怎么格式化 df_cut.value_counts()呢。这个输出的是类似于
（-3，5] 8
（ 5，13] 5
这样的格式，怎么变成
-3 5 8
5 13 5

ladypxy

2019-11-17 20:48:42 +08:00

@wangyzj 这个写法只是把 list 的元素按照 N 来分成新的列表。而不是根据最大最小值来计算区间然后分配。而且还会把最大值忽略。。

wangyzj

2019-11-18 00:51:15 +08:00

@ladypxy 完，理解错你的意思了
你要的是这个意思？
mylist = sorted(mylist)
newlist = []
templist = []
min = mylist[0]
max = mylist[len(mylist)-1]
delta = (max-min) / N
next = min + delta
j = 0
for i in mylist:
if i <= next:
templist.append(i)
if i >= next:
newlist.append(templist)
next = next+delta
templist = []
templist.append(i)
j += 1
if j == len(mylist):
newlist.append(templist)

print(newlist)

wangyzj

2019-11-18 00:56:16 +08:00

@ladypxy 完，理解错你的意思了
你要的是这个意思？
mylist = sorted(mylist)
newlist = []
templist = []
min = mylist[0]
max = mylist[len(mylist)-1]
delta = (max-min) / (N-1)
next = min + delta
j = 0
for i in mylist:
if i <= next:
templist.append(i)
if i >= next:
newlist.append(templist)
next = next+delta
templist = []
templist.append(i)
j += 1
if j == len(mylist):
newlist.append(templist)

print(newlist)