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
.