Python - 来自给定字符的 K 长度组合

给定一个字符串，以单行方式生成 K 个长度的组合。

Input : test_str = ‘gfg’, K = 3 
Output : [‘ggg’, ‘ggf’, ‘ggg’, ‘gfg’, ‘gff’, ‘gfg’, ‘ggg’, ‘ggf’, ‘ggg’, ‘fgg’, ‘fgf’, ‘fgg’, ‘ffg’, ‘fff’, ‘ffg’, ‘fgg’, ‘fgf’, ‘fgg’, ‘ggg’, ‘ggf’, ‘ggg’, ‘gfg’, ‘gff’, ‘gfg’, ‘ggg’, ‘ggf’, ‘ggg’] 
Explanation : All combinations of K length extracted.

Input : test_str = ‘G4G’, K = 2 
Output : [‘GG’, ‘G4’, ‘GG’, ‘4G’, ’44’, ‘4G’, ‘GG’, ‘G4’, ‘GG’] 
Explanation : All combinations of K length extracted. 
 

方法 #1：使用itertools.product() + join() + map()

该任务可以由 product() 使用重复参数执行，但返回结果在单个字符的元组列表中。这些都可以使用 join() 和 map() 连接起来。

Python3

# Python3 code to demonstrate working of 
# K length Combinations from given characters shorthand
# Using itertools.product() + join() + map()
from itertools import product
  
# initializing string
test_str = 'gf4g'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing K 
K = 2
  
# map and join() used to change return data type
res = list(map(''.join, product(test_str, repeat = K)))
      
# printing result 
print("The generated Combinations : " + str(res))

输出：

The original string is : gf4g
The generated Combinations : [‘gg’, ‘gf’, ‘g4’, ‘gg’, ‘fg’, ‘ff’, ‘f4’, ‘fg’, ‘4g’, ‘4f’, ’44’, ‘4g’, ‘gg’, ‘gf’, ‘g4’, ‘gg’]

方法 #2：使用 itertools.product() + 列表理解

在这种情况下，列表理解用于连接元素的任务。

蟒蛇3

# Python3 code to demonstrate working of 
# K length Combinations from given characters shorthand
# Using itertools.product() + join() + map()
from itertools import product
  
# initializing string
test_str = 'gfg'
  
# printing original string
print("The original string is : " + str(test_str))
  
# initializing K 
K = 2
  
# list comprehension + join() used to change return data type
res = [''.join(ele) for ele in product(test_str, repeat = K)]
      
# printing result 
print("The generated Combinations : " + str(res))

输出：

The original string is : gfg
The generated Combinations : [‘gg’, ‘gf’, ‘gg’, ‘fg’, ‘ff’, ‘fg’, ‘gg’, ‘gf’, ‘gg’]