Series objects are mutable and cannot be hashed error

Question

I am trying to get the following script to work  The input file consists of 3 columns  gene association type  gene name  and disease name   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   I keep getting an error that says      Series objects are mutable and cannot be hashed   Any help would be dearly appreciated

User · Answer

gene name   no headers iloc 1   1     This creates a DataFrame because you passed a list of columns  single  but still a list   When you later do this   gene name x    you now have a Series object with a single value  You can t hash the Series   The solution is to create 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    Also  where you have orph dict gene name x      1  I m guessing that s a typo and you really mean orph dict gene name x      1 to increment the counter

User · Answer

Shortly  gene name x  is a mutable object so it cannot be hashed  To use an object as a key in a dictionary  python needs to use its hash value  and that s why you get an error   Further explanation   Mutable objects are objects which value can be changed  For example  list is a mutable object  since you can append to it  int is an immutable object  because you can t change it  When you do   a   5  a   3    You don t change the value of a  you create a new object and make a point to its value   Mutable objects cannot be hashed  See this answer   To solve your problem  you should use immutable objects as keys in your dictionary  For example  tuple  string  int

[python] "Series objects are mutable and cannot be hashed" error

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