Home/ Questions/Stabilizing the error with the best answers: typeerror: 'series' objects are mutable, thus they cannot be hashed
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Hugo Guerin
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Asked: 2022-05-12T09:20:18+00:00 In:

Stabilizing the error with the best answers: typeerror: ‘series’ objects are mutable, thus they cannot be hashed

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In the process of completing my work, I encountered the following problem:

Series objects are mutable and cannot be hashed

Below is the code I ran:

cols = ['Gene type', 'Gene name', 'Disorder name']
 no_headers = pd.read_csv('orphanet_infoneeded.csv', sep=',',header=None,names=cols)
 
 gene_type = no_headers.iloc[1:,[0]]
 gene_name = no_headers.iloc[1:,[1]]
 disease_name = no_headers.iloc[1:,[2]]
 
 query = 'Disease-causing germline mutation(s) in' ###add query as required
 
 orph_dict = {}
 
 for x in gene_name:
  if gene_name[x] in orph_dict:
  if gene_type[x] == query:
  orph_dict[gene_name[x]]=+ 1
  else:
  pass
  else:
  orph_dict[gene_name[x]] = 0

What’s causing it, and how can it be resolved in the “typeerror: ‘series’ objects are mutable, thus they cannot be hashed“ in the python?

typeerror
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2 Answers

  1. Best Answer
    Expert

    The cause:

    gene_name = no_headers.iloc[1:,[1]]

    This error happens because you passed a list of columns (single, but still a list). When you later do this:

    gene_name[x]

    Now you have a Series object with a single value, so can’t hash the Series.

    Solution: You can resolve the error by creating Series from the start.

    gene_type = no_headers.iloc[1:,0]
gene_name = no_headers.iloc[1:,1]
disease_name = no_headers.iloc[1:,2]
    • 16

  2. gene_name[x], short for gene_name[x], is a mutable object that cannot be hashed. Python must use the object’s hash value to create a dictionary key. This is why you get an error.

    Additional explanation

    Mutable objects are objects whose value can be altered. list, for example, is a mutable item because you can add to it. int, on the other hand, is immutable. You can’t modify it. If you do:

    a = 5;
a = 3;

    a‘s value is not changed. Instead, create a new object to point a to it.

    It is impossible to hash out mutable objects. 

    You should use immutable objects in your dictionary to solve your problem. tuple, string and int are examples.

    • 19

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