'NoneType' object has no attribute 'insert' Python List append insert

Question

I have the following problem: I create an array and then I turned it to a list, to which I want to add two more values. I have tried with append and with insert but I becoma the error message: 'NoneType' object has no attribute 'insert'. That means that my list is not a list. Here is what I am trying to do:

f = 25
bi = np.arange(-f, f + 5, 5)
beta = bi.tolist()
print "beta:", beta

d = np.arange(-f, f + 5, f / 3)
di = d.tolist()
print "di:", di

dj = di.insert(1, -f / 2)
print "dj:", dj 

dk = dj.insert(5, f / 2)
dw = sorted(dk)
delta = [round(elem, 0) for elem in dw]
print "delta:", delta

Has anyone an idea what I am doing wrong or how can Imake it work? Moreover the "sorted" seems also not to be working.

always add full error message.

furas
– furas

2016-01-20 14:32:07 +00:00
Commented Jan 20, 2016 at 14:32 — furas
– furas, Commented Jan 20, 2016 at 14:32

OmPrakash · Accepted Answer · 2016-01-21 16:09:18Z

1

Problem is on 9th line: list insert method does not return anything (means None),

dj=di.insert(1,-f/2)

so dj will get assigned None so this statement will raise an error.

dk=dj.insert(5,f/2)

Now Try This:

f=25
bi=np.arange(-f,f+5,5)
beta=bi.tolist()
print "beta:", beta
d=np.arange(-f,f+5,f/3)
di=d.tolist()
print "di:", di
di.insert(1,-f/2)
print "di:", di
di.insert(5,f/2)
dw=sorted(di)
delta=[round(elem, 0) for elem in dw]
print "delta:", delta

edited Jan 21, 2016 at 16:09

answered Jan 20, 2016 at 14:31

OmPrakash

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1 Comment

GeMa Over a year ago

Thank you! That works. Although I don't get why in dj is assigned NONE. Is assigned di.insert.

furas · Accepted Answer · 2016-01-20 14:31:09Z

1

insert() and append() doesnt't return new list so you can't assign it to dj

di.insert(1,-f/2)

print "di:", di

di.insert(5,f/2)

print "di:", di

dw = sorted(di)

answered Jan 20, 2016 at 14:31

furas

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Comments

tglaria · Accepted Answer · 2016-01-20 14:31:54Z

0

Your problem is in these lines:

dj=di.insert(1,-f/2)
dk=dj.insert(5,f/2)

di.insert() inserts something into the list di and returns None, so you're assigning None to dj.

THEN, you're trying to call the function insert() in the 'value' None which doesn't have it so you're getting an error.

answered Jan 20, 2016 at 14:31

tglaria

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Comments

ishaan · Accepted Answer · 2016-01-20 14:45:16Z

0

Yeah that's happening because di.insert() doesn't actually return anything and that's why dj is a NoneType object.

Do this instead

from copy import copy
dj=copy(di)
dj.insert(1,-f/2)

edited Jan 20, 2016 at 14:45

answered Jan 20, 2016 at 14:32

ishaan

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2 Comments

Open AI - Opting Out Over a year ago

dj and di will be names for the same object.

ishaan Over a year ago

Yeah that's why he needs a copy of the list. copy.copy should work. Provided OP wants a new copy of the list for whatever he's doing.

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