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1. 使用enumerate() 列表解析
# initializing list
test_list …我们可以给列表中的所有数字分配一个唯一的值重复时它会保留给它的值。这是一个非常常见的问题在Web开发中处理物品id时会遇到。让我们讨论一下解决这个问题的一些方法。
1. 使用enumerate() 列表解析
# initializing list
test_list [1, 4, 6, 1, 4, 5, 6]# printing the original list
print(The original list is : str(test_list))# using list comprehension enumerate
# assign unique value to list elements
temp {i: j for j, i in enumerate(set(test_list))}
res [temp[i] for i in test_list]# printing result
print(The unique value list is : str(res))
输出
The original list is : [1, 4, 6, 1, 4, 5, 6]
The unique value list is : [0, 1, 3, 0, 1, 2, 3]2. 使用setdefault() map() count()
from itertools import count# initializing list
test_list [1, 4, 6, 1, 4, 5, 6]# printing the original list
print(The original list is : str(test_list))# using setdefault() map() count()
# assign unique value to list elements
res list(map({}.setdefault, test_list, count()))# printing result
print(The unique value list is : str(res))
输出
The original list is : [1, 4, 6, 1, 4, 5, 6]
The unique value list is : [0, 1, 2, 0, 1, 5, 2]3. 使用innot in操作符和index
# initializing list
test_list [1, 4, 6, 1, 4, 5, 6]# printing the original list
print (The original list is : str(test_list))# assign unique value to list elements
x[]
for i in test_list:if i not in x:x.append(i)
res[]
for i in test_list:res.append(x.index(i))# printing result
print (The unique value list is : str(res))
输出
The original list is : [1, 4, 6, 1, 4, 5, 6]
The unique value list is : [0, 1, 2, 0, 1, 3, 2]4. 使用reduce()
from functools import reducetest_list [1, 4, 6, 1, 4, 5, 6]
# printing the original list
print (The original list is : str(test_list))unique_list reduce(lambda l, x: l [x] if x not in l else l, test_list, [])res [unique_list.index(i) for i in test_list]
# printing result
print (The unique value list is : str(res))
输出
The original list is : [1, 4, 6, 1, 4, 5, 6]
The unique value list is : [0, 1, 2, 0, 1, 3, 2]5. 使用sorted()和bisect_left()
import bisect# initializing list
test_list [1, 4, 6, 1, 4, 5, 6]# printing the original list
print (The original list is : str(test_list))# assign unique value to list elements using sorted() and bisect_left()
sorted_list sorted(test_list)
res []
for i in test_list:idx bisect.bisect_left(sorted_list, i)res.append(idx)# printing result
print (The unique value list is : str(res))
输出
The original list is : [1, 4, 6, 1, 4, 5, 6]
The unique value list is : [0, 2, 5, 0, 2, 4, 5]6. 使用numpy
import numpy as nptest_list [1, 4, 6, 1, 4, 5, 6]
# printing the original list
print(The original list is:, test_list)# convert list to numpy array
arr np.array(test_list)# get unique values and their indices
unique_arr, unique_indices np.unique(arr, return_inverseTrue)# get indices of unique values for each element in original list
res unique_indices.tolist()# printing result
print(The unique value list is:, res)输出
The original list is: [1, 4, 6, 1, 4, 5, 6]
The unique value list is: [0, 1, 3, 0, 1, 2, 3]
