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Solve the problem of the arrangement and combination of elements in the list. I have encountered this problem several times before. I have not paid much attention to it. Recently, I encountered a lot of permutation and combination problems when doing the problem. I wrote it manually before. Later I learned that you can directly use Python's built-in module to complete this work. Today I use Python's itertools module to complete this work. A total of four problems are solved:
1. Generate arrangement, elements in the list are not allowed to appear repeatedly
2. Generate an arrangement, the elements in the list can appear repeatedly
3. Generate combinations, unlimited number of elements, elements in the list are not allowed to appear repeatedly
4. Generate combinations, unlimited number of elements, elements in the list can appear repeatedly
因为大家都有排列组合的知识这里就不累赘了，问题很简单，下面看具体的实现：
#!usr/bin/env python
#encoding:utf-8
'''''
__Author__:沂水寒城
功能：求解列表中元素的排列和组合问题
'''
from itertools import product
from itertools import combinations
import itertools
def test_func1(num_list):
'''''
生成排列
列表中元素不允许重复出现
排列数计算为：n！，其中n为num_list列表中元素个数
'''
tmp_list = itertools.permutations(num_list)
res_list=[]
for one in tmp_list:
res_list.append(one)
print res_list
print '元素不允许重复出现排列总数为:', len(res_list)
def test_func11(num_list):
'''''
生成排列
列表中元素可以重复出现
排列总数计算为：(n*n*n...*n)，一共n个n相乘
'''
num=len(num_list)
res_list=list(product(num_list,repeat=num))
print res_list
print '元素可以重复出现排列总数为:', len(res_list)
def test_func2(num_list):
'''''
生成组合,不限元素个数
列表中元素不允许重复出现
组合数计算为：2^n，其中n为num_list列表中元素个数
'''
res_list=[]
for i in range(len(num_list)+1):
res_list+=list(combinations(num_list, i))
print res_list
print '元素不允许重复出现组合总数为:', len(res_list)
def test_func22(num_list):
'''''
生成组合,不限元素个数
列表中元素可以重复出现
'''
res_list=[]
num_list1=[str(i) for i in num_list]
for i in range(0,len(num_list)+1):
res_list+=[''.join(x) for x in itertools.product(*[num_list1] * i)]
print res_list
print '元素可以重复出现组合总数为:', len(res_list)
if __name__ == '__main__':
num_list=[1,2,3,4]
test_func1(num_list)
print '-------------------------------------'
test_func11(num_list)
print '-------------------------------------'
test_func2(num_list)
print '-------------------------------------'
test_func22(num_list)
The results are as follows:
[(1, 2, 3, 4), (1, 2, 4, 3), (1, 3, 2, 4), (1, 3, 4, 2), (1, 4, 2, 3), (1, 4, 3, 2), (2, 1, 3, 4), (2, 1, 4, 3), (2, 3, 1, 4), (2, 3, 4, 1), (2, 4, 1, 3), (2, 4, 3, 1), (3, 1, 2, 4), (3, 1, 4, 2), (3, 2, 1, 4), (3, 2, 4, 1), (3, 4, 1, 2), (3, 4, 2, 1), (4, 1, 2, 3), (4, 1, 3, 2), (4, 2, 1, 3), (4, 2, 3, 1), (4, 3, 1, 2), (4, 3, 2, 1)]
元素不允许重复出现排列总数为: 24
-------------------------------------
[(1, 1, 1, 1), (1, 1, 1, 2), (1, 1, 1, 3), (1, 1, 1, 4), (1, 1, 2, 1), (1, 1, 2, 2), (1, 1, 2, 3), (1, 1, 2, 4), (1, 1, 3, 1), (1, 1, 3, 2), (1, 1, 3, 3), (1, 1, 3, 4), (1, 1, 4, 1), (1, 1, 4, 2), (1, 1, 4, 3), (1, 1, 4, 4), (1, 2, 1, 1), (1, 2, 1, 2), (1, 2, 1, 3), (1, 2, 1, 4), (1, 2, 2, 1), (1, 2, 2, 2), (1, 2, 2, 3), (1, 2, 2, 4), (1, 2, 3, 1), (1, 2, 3, 2), (1, 2, 3, 3), (1, 2, 3, 4), (1, 2, 4, 1), (1, 2, 4, 2), (1, 2, 4, 3), (1, 2, 4, 4), (1, 3, 1, 1), (1, 3, 1, 2), (1, 3, 1, 3), (1, 3, 1, 4), (1, 3, 2, 1), (1, 3, 2, 2), (1, 3, 2, 3), (1, 3, 2, 4), (1, 3, 3, 1), (1, 3, 3, 2), (1, 3, 3, 3), (1, 3, 3, 4), (1, 3, 4, 1), (1, 3, 4, 2), (1, 3, 4, 3), (1, 3, 4, 4), (1, 4, 1, 1), (1, 4, 1, 2), (1, 4, 1, 3), (1, 4, 1, 4), (1, 4, 2, 1), (1, 4, 2, 2), (1, 4, 2, 3), (1, 4, 2, 4), (1, 4, 3, 1), (1, 4, 3, 2), (1, 4, 3, 3), (1, 4, 3, 4), (1, 4, 4, 1), (1, 4, 4, 2), (1, 4, 4, 3), (1, 4, 4, 4), (2, 1, 1, 1), (2, 1, 1, 2), (2, 1, 1, 3), (2, 1, 1, 4), (2, 1, 2, 1), (2, 1, 2, 2), (2, 1, 2, 3), (2, 1, 2, 4), (2, 1, 3, 1), (2, 1, 3, 2), (2, 1, 3, 3), (2, 1, 3, 4), (2, 1, 4, 1), (2, 1, 4, 2), (2, 1, 4, 3), (2, 1, 4, 4), (2, 2, 1, 1), (2, 2, 1, 2), (2, 2, 1, 3), (2, 2, 1, 4), (2, 2, 2, 1), (2, 2, 2, 2), (2, 2, 2, 3), (2, 2, 2, 4), (2, 2, 3, 1), (2, 2, 3, 2), (2, 2, 3, 3), (2, 2, 3, 4), (2, 2, 4, 1), (2, 2, 4, 2), (2, 2, 4, 3), (2, 2, 4, 4), (2, 3, 1, 1), (2, 3, 1, 2), (2, 3, 1, 3), (2, 3, 1, 4), (2, 3, 2, 1), (2, 3, 2, 2), (2, 3, 2, 3), (2, 3, 2, 4), (2, 3, 3, 1), (2, 3, 3, 2), (2, 3, 3, 3), (2, 3, 3, 4), (2, 3, 4, 1), (2, 3, 4, 2), (2, 3, 4, 3), (2, 3, 4, 4), (2, 4, 1, 1), (2, 4, 1, 2), (2, 4, 1, 3), (2, 4, 1, 4), (2, 4, 2, 1), (2, 4, 2, 2), (2, 4, 2, 3), (2, 4, 2, 4), (2, 4, 3, 1), (2, 4, 3, 2), (2, 4, 3, 3), (2, 4, 3, 4), (2, 4, 4, 1), (2, 4, 4, 2), (2, 4, 4, 3), (2, 4, 4, 4), (3, 1, 1, 1), (3, 1, 1, 2), (3, 1, 1, 3), (3, 1, 1, 4), (3, 1, 2, 1), (3, 1, 2, 2), (3, 1, 2, 3), (3, 1, 2, 4), (3, 1, 3, 1), (3, 1, 3, 2), (3, 1, 3, 3), (3, 1, 3, 4), (3, 1, 4, 1), (3, 1, 4, 2), (3, 1, 4, 3), (3, 1, 4, 4), (3, 2, 1, 1), (3, 2, 1, 2), (3, 2, 1, 3), (3, 2, 1, 4), (3, 2, 2, 1), (3, 2, 2, 2), (3, 2, 2, 3), (3, 2, 2, 4), (3, 2, 3, 1), (3, 2, 3, 2), (3, 2, 3, 3), (3, 2, 3, 4), (3, 2, 4, 1), (3, 2, 4, 2), (3, 2, 4, 3), (3, 2, 4, 4), (3, 3, 1, 1), (3, 3, 1, 2), (3, 3, 1, 3), (3, 3, 1, 4), (3, 3, 2, 1), (3, 3, 2, 2), (3, 3, 2, 3), (3, 3, 2, 4), (3, 3, 3, 1), (3, 3, 3, 2), (3, 3, 3, 3), (3, 3, 3, 4), (3, 3, 4, 1), (3, 3, 4, 2), (3, 3, 4, 3), (3, 3, 4, 4), (3, 4, 1, 1), (3, 4, 1, 2), (3, 4, 1, 3), (3, 4, 1, 4), (3, 4, 2, 1), (3, 4, 2, 2), (3, 4, 2, 3), (3, 4, 2, 4), (3, 4, 3, 1), (3, 4, 3, 2), (3, 4, 3, 3), (3, 4, 3, 4), (3, 4, 4, 1), (3, 4, 4, 2), (3, 4, 4, 3), (3, 4, 4, 4), (4, 1, 1, 1), (4, 1, 1, 2), (4, 1, 1, 3), (4, 1, 1, 4), (4, 1, 2, 1), (4, 1, 2, 2), (4, 1, 2, 3), (4, 1, 2, 4), (4, 1, 3, 1), (4, 1, 3, 2), (4, 1, 3, 3), (4, 1, 3, 4), (4, 1, 4, 1), (4, 1, 4, 2), (4, 1, 4, 3), (4, 1, 4, 4), (4, 2, 1, 1), (4, 2, 1, 2), (4, 2, 1, 3), (4, 2, 1, 4), (4, 2, 2, 1), (4, 2, 2, 2), (4, 2, 2, 3), (4, 2, 2, 4), (4, 2, 3, 1), (4, 2, 3, 2), (4, 2, 3, 3), (4, 2, 3, 4), (4, 2, 4, 1), (4, 2, 4, 2), (4, 2, 4, 3), (4, 2, 4, 4), (4, 3, 1, 1), (4, 3, 1, 2), (4, 3, 1, 3), (4, 3, 1, 4), (4, 3, 2, 1), (4, 3, 2, 2), (4, 3, 2, 3), (4, 3, 2, 4), (4, 3, 3, 1), (4, 3, 3, 2), (4, 3, 3, 3), (4, 3, 3, 4), (4, 3, 4, 1), (4, 3, 4, 2), (4, 3, 4, 3), (4, 3, 4, 4), (4, 4, 1, 1), (4, 4, 1, 2), (4, 4, 1, 3), (4, 4, 1, 4), (4, 4, 2, 1), (4, 4, 2, 2), (4, 4, 2, 3), (4, 4, 2, 4), (4, 4, 3, 1), (4, 4, 3, 2), (4, 4, 3, 3), (4, 4, 3, 4), (4, 4, 4, 1), (4, 4, 4, 2), (4, 4, 4, 3), (4, 4, 4, 4)]
元素可以重复出现排列总数为: 256
-------------------------------------
[(), (1,), (2,), (3,), (4,), (1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4), (1, 2, 3), (1, 2, 4), (1, 3, 4), (2, 3, 4), (1, 2, 3, 4)]
元素不允许重复出现组合总数为: 16
-------------------------------------
['', '1', '2', '3', '4', '11', '12', '13', '14', '21', '22', '23', '24', '31', '32', '33', '34', '41', '42', '43', '44', '111', '112', '113', '114', '121', '122', '123', '124', '131', '132', '133', '134', '141', '142', '143', '144', '211', '212', '213', '214', '221', '222', '223', '224', '231', '232', '233', '234', '241', '242', '243', '244', '311', '312', '313', '314', '321', '322', '323', '324', '331', '332', '333', '334', '341', '342', '343', '344', '411', '412', '413', '414', '421', '422', '423', '424', '431', '432', '433', '434', '441', '442', '443', '444', '1111', '1112', '1113', '1114', '1121', '1122', '1123', '1124', '1131', '1132', '1133', '1134', '1141', '1142', '1143', '1144', '1211', '1212', '1213', '1214', '1221', '1222', '1223', '1224', '1231', '1232', '1233', '1234', '1241', '1242', '1243', '1244', '1311', '1312', '1313', '1314', '1321', '1322', '1323', '1324', '1331', '1332', '1333', '1334', '1341', '1342', '1343', '1344', '1411', '1412', '1413', '1414', '1421', '1422', '1423', '1424', '1431', '1432', '1433', '1434', '1441', '1442', '1443', '1444', '2111', '2112', '2113', '2114', '2121', '2122', '2123', '2124', '2131', '2132', '2133', '2134', '2141', '2142', '2143', '2144', '2211', '2212', '2213', '2214', '2221', '2222', '2223', '2224', '2231', '2232', '2233', '2234', '2241', '2242', '2243', '2244', '2311', '2312', '2313', '2314', '2321', '2322', '2323', '2324', '2331', '2332', '2333', '2334', '2341', '2342', '2343', '2344', '2411', '2412', '2413', '2414', '2421', '2422', '2423', '2424', '2431', '2432', '2433', '2434', '2441', '2442', '2443', '2444', '3111', '3112', '3113', '3114', '3121', '3122', '3123', '3124', '3131', '3132', '3133', '3134', '3141', '3142', '3143', '3144', '3211', '3212', '3213', '3214', '3221', '3222', '3223', '3224', '3231', '3232', '3233', '3234', '3241', '3242', '3243', '3244', '3311', '3312', '3313', '3314', '3321', '3322', '3323', '3324', '3331', '3332', '3333', '3334', '3341', '3342', '3343', '3344', '3411', '3412', '3413', '3414', '3421', '3422', '3423', '3424', '3431', '3432', '3433', '3434', '3441', '3442', '3443', '3444', '4111', '4112', '4113', '4114', '4121', '4122', '4123', '4124', '4131', '4132', '4133', '4134', '4141', '4142', '4143', '4144', '4211', '4212', '4213', '4214', '4221', '4222', '4223', '4224', '4231', '4232', '4233', '4234', '4241', '4242', '4243', '4244', '4311', '4312', '4313', '4314', '4321', '4322', '4323', '4324', '4331', '4332', '4333', '4334', '4341', '4342', '4343', '4344', '4411', '4412', '4413', '4414', '4421', '4422', '4423', '4424', '4431', '4432', '4433', '4434', '4441', '4442', '4443', '4444']
元素可以重复出现组合总数为: 341
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