Convert list to int Python [duplicate]

Question

I have this code:

import numpy as np
x= list(np.arange(1,9,0.5))
d = x + 2
print(d)

However the output gave this kind of error:

can only concatenate list not "int" to list

I'm trying to convert list to int using this code:

int(list(x))

But it gave another error. Can you please help me solving this. Thank you!

What output do you want? Do you want to append 2 to the list, or add 2 to each item in the list (or something else entirely)? — DavidW
– DavidW, Commented Mar 14, 2022 at 9:43
Not sure what you attempting in trying to cast a list to an int, perhaps you want to cast each element to an int? — Harry Jones
– Harry Jones, Commented Mar 14, 2022 at 9:47
I want to generate range of number from 1-9, then, each number will add to 2. Or d= x + 2. — nobel
– nobel, Commented Mar 14, 2022 at 9:52
I've marked a duplicate which does what you ask. However if you just keep the Numpy array (and don't convert it to a list) then you add to it directly — DavidW
– DavidW, Commented Mar 14, 2022 at 10:01

Harry Jones · Accepted Answer · 2022-03-14 10:04:15Z

0

If you want to add 2 to each element, you need to use a map function like so:

d = list(map(lambda y: y + 2, x))

edited Mar 14, 2022 at 10:04

answered Mar 14, 2022 at 9:46

Harry Jones

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2 Comments

nobel Over a year ago

The output must be equal to: [3, 3.5, 4.0, 4. 5,......]. All numbers must be added to 2 >

Harry Jones Over a year ago

I think I've got what you mean, updated my answer

BiRD · Accepted Answer · 2022-03-14 10:09:58Z

-1

The “TypeError: can only concatenate list (not “int”) to list” error is raised when you try to concatenate an integer to a list.

This error is raised because only lists can be concatenated to lists. To solve this error, use the append() or the '+' method to add an item to a list.

d = x + [2]
#or
x.append(2)

Here are some other ways to do it: link

EDIT:

if you want to add 2 to every value in x:

1.x = list(np.arange(1,9,0.5) + 2)

or

2.x = [i+2 for i in x]

edited Mar 14, 2022 at 10:09

answered Mar 14, 2022 at 9:55

BiRD

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