如何在Python中只解析列表中的重复项？

Question

例如，如果我有一个基因名列表，并且我想创建一个只包含重复基因的新列表，我该怎么做？你知道吗

原始列表示例：

RGN
RBM10
ARAF
ZNF630
FTSJ1
SLC35A2
SLC35A2
SLC35A2
MAGIX
DGKK
XAGE1B
XAGE1B
SMC1A
FAM120C
CXorf49
CXorf49B
CHIC1
ABCB7
PBDC1
FGF16
ATP7A
CYLC1
TSPAN6
BTK
BTK
TCEAL4
TEX13A
FRMPD3
PRPS1
COL4A6
COL4A6
COL4A6

例如，SLC35A2会出现在新列表中，因为它会重复3次。你知道吗

请建议。你知道吗

Answer 1

• 时间复杂度=O(n)
• 空间复杂性=O(n)

• 代码：

  def get_duplicates(array):
      seen = set([])
      results = set([])
      for element in array:
          if element in seen:
              results.add(element)
          else:
              seen.add(element)
  
      return list(results)
  
  input_array = "RGN RBM10 ARAF ZNF630 FTSJ1 SLC35A2 SLC35A2 SLC35A2 MAGIX DGKK XAGE1B XAGE1B SMC1A FAM120C CXorf49 CXorf49B CHIC1 ABCB7 PBDC1 FGF16 ATP7A CYLC1 TSPAN6 BTK BTK TCEAL4 TEX13A FRMPD3 PRPS1 COL4A6 COL4A6 COL4A6"
  input_array = input_array.split()
  duplicates = get_duplicates(input_array)
  print(duplicates)
  

• 输出：
  ['COL4A6', 'SLC35A2', 'XAGE1B', 'BTK']

Answer 2

你可以这样做：

listOfGenes = "RGN RBM10 ARAF ZNF630 FTSJ1 SLC35A2 SLC35A2 SLC35A2 MAGIX DGKK XAGE1B XAGE1B SMC1A FAM120C CXorf49 CXorf49B CHIC1 ABCB7 PBDC1 FGF16 ATP7A CYLC1 TSPAN6 BTK BTK TCEAL4 TEX13A FRMPD3 PRPS1 COL4A6 COL4A6 COL4A6".split(" ")

genesOccurences = {}
for gene in listOfGenes:
    occurence = genesOccurences.get(gene, 0)
    genesOccurences[gene] = occurence + 1

print(genesOccurences) # will print a dictionary with every gene and how often it is occurring

filteredGeneList = [ key for key in genesOccurences if genesOccurences[key] > 1 ]
print(filteredGeneList) # will print only those genes occurring > 1 times.

Answer 3

collections.Counter使这个过程变得快速而琐碎：

from collections import Counter

# Using other answer's listOfGenes for convenience
listOfGenes = "RGN RBM10 ARAF ZNF630 FTSJ1 SLC35A2 SLC35A2 SLC35A2 MAGIX DGKK XAGE1B XAGE1B SMC1A FAM120C CXorf49 CXorf49B CHIC1 ABCB7 PBDC1 FGF16 ATP7A CYLC1 TSPAN6 BTK BTK TCEAL4 TEX13A FRMPD3 PRPS1 COL4A6 COL4A6 COL4A6".split()

# Actual work is a one-liner; count them all, keep those with count of 2 or more
duplicates = [gene for gene, cnt in Counter(listOfGenes).items() if cnt >= 2]

在cpython3.6和更高版本（以及所有Python解释器一旦达到3.7）中提供插入顺序dict，则duplicateslist将按listOfGenes中第一次出现的顺序排序；在3.5和更早版本中，它将具有任意顺序。你知道吗