CODEWITHSUNDEEP
pythontypeerror
user3241976
user3241976

Reputation: 69

TypeError: 'int' object does not support item assignment

p=range(0,1200,10)
lenp=len(p)
rp=1.331
po=1000
T=280
Temp=(lenp)

for i in p:
    Temp[i]=T*(p[i]/po)**rp
print T

Im getting this error and don't know how to fix it...

Temp[i]=T*(p[i]/po)**rp

TypeError: 'int' object does not support item assignment

Upvotes: 5

Views: 49195

Answers (4)

Hemanth Kollipara
Hemanth Kollipara

Reputation: 1131

The mistake is that when we assign a (number) to x, this is what is actually happening,

>>> x = (50)
>>> x
50

So if you want to create an empty list , you can do it this way

rows = 5
cols = 3
matrix = [[0 for c in range(cols)] for r in range(rows)]

Its gonna create something like this one,

>>> matrix
[[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]

Upvotes: 1

Martijn Pieters
Martijn Pieters

Reputation: 1121226

You are presumably trying to build a list of length lenp here. You'd need to create a list by multiplication here:

Temp = [None] * lenp

but you'd be better off building the list by appending to it:

Temp = []
for i in p:
    Temp.append(T * (i / po) ** rp)

where you don't use p[i] but i directly; Python for loops are for each loops really.

Your range() produces values in the series [0, 10, 20, ... 1200) and the for loop assigns each of those values to i per iteration. If you use i to index into p again you'd run into problems; p[0] would still be 0, but p[10] would then be 100, p[20] is 200, etc. until p[120] throws an IndexError because there are only 119 different values in that range.

You can collapse the for loop appending to Temp into a list comprehension to build the list in one go:

rp=1.331
po=1000
T=280

Temp = [T * (i / po) ** rp for i in range(0, 1200, 10)]

Upvotes: 5

Blckknght
Blckknght

Reputation: 104682

There are a couple of issues in your code.

The most immediate one is that your Temp value is not a sequence that you can assign things to, just an integer (the parentheses don't do anything). While you could make it into a tuple by adding a comma, that still won't let you assign values into Temp after it has been created (tuples are immutable). Instead, you probably want a list.

However, there's another issue with your loop. A for loop like for value in sequence assigns values from the sequence to the variable value. It doesn't assign indexes! If you need indexes, you can either use enumerate or use a different looping construct, such as a list comprehension.

Here's a minimally changed version of your code that first creates a list of lenp zeros, then replaces their values with the computed ones:

p=range(0,1200,10)
lenp=len(p)
rp=1.331
po=1000
T=280
Temp=[0]*lenp

for i, p_value in enumerate(p):
    Temp[i]=T*(p_value/po)**rp
print T

Here's a more pythonic version that uses a list comprehension instead of an ordinary loop:

rp=1.331
po=1000
T=280
Temp = [T*(p_value/po)**rp for p_value in range(0,1200,10)]

Upvotes: 3

arshajii
arshajii

Reputation: 129477

Your Temp is not a tuple, it's just an integer in parenthesis. You can fix this with a simple ,. Consider the following:

>>> x = (42)  # not a tuple
>>> x[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object has no attribute '__getitem__'
>>> 
>>> x = (42,)  # tuple
>>> x[0]
42

However, tuples are immutable, and you cannot perform such an assignment:

>>> x[0] = 0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment

You can fix this issue by using a list instead.

Upvotes: 1

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