Python TypeError object of type NoneType has no len

Question

I am getting an error from this Python code   with open  names   as f      names   f read       names   names split   n       names pop len names  - 1      names   shuffle names      f close    assert len names   gt  100   Error   Python  TypeError  object of type  NoneType  has no len     The assert statement is throwing this error  what am I doing wrong

User · Answer

What is the purpose of this   names   list      Also  no   required in Python   Do you want   names        or    names   list     at the start of your program instead  Though given your particular code  there s no need for this statement to create this names variable since you do so later when you read data into it from your file    JBernardo has already pointed out the other  and more major  problem with the code

User · Answer

You don t need to assign names to list or    or anything else until you wish to use it   It s neater to use a list comprehension to make the list of names   shuffle modifies the list you pass to it  It always returns None  If you are using a context manager  with      you don t need to close the file explicitly  from random import shuffle  with open  names   as f      names    name rstrip   for name in f if not name isspace        shuffle names   assert len names   gt  100

User · Answer

shuffle names  is an in-place operation  Drop the assignment   This function returns None and that s why you have the error    TypeError  object of type  NoneType  has no len

User · Answer

I was faces this issue but after change object into str  problem solved  str fname  isalpha

[python] Python: TypeError: object of type 'NoneType' has no len()

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