Python array spread

As Alexander points out in the comments, list addition is concatenation.

a = [1,2,3,4]
b = [10] + a  # N.B. that this is NOT `10 + a`
# [10, 1, 2, 3, 4]
You can also use list.extend

a = [1,2,3,4]
b = [10]
b.extend(a)
# b is [10, 1, 2, 3, 4]
and newer versions of Python allow you to (ab)use the splat (*) operator.

b = [10, *a]
# [10, 1, 2, 3, 4]
Your choice may reflect a need to mutate (or not mutate) an existing list, though.

a = [1,2,3,4]
b = [10]
DONTCHANGE = b

b = b + a  # (or b += a)
# DONTCHANGE stays [10]
# b is assigned to the new list [10, 1, 2, 3, 4]

b = [*b, *a]
# same as above

b.extend(a)
# DONTCHANGE is now [10, 1, 2, 3, 4]! Uh oh!
# b is too, of course...

Source: stackoverflow.com

Similar codes

1 vote257 views1 answer
How to count in a loop python
Python
1 vote262 views1 answer
Delete files with same extensions
Python
0 vote281 views1 answer
Dataflair python
Python
0 vote256 views2 answers
Funcion que reciba una cadena en python
Python
0 vote258 views1 answer
Roll a dice
Python
0 vote277 views2 answers
Selenium delete cookies python
Python
2 votes299 views1 answer
Not x axis labels python
Python
0 vote285 views1 answer
Python : read all the contents of the file into a string (use of 'with open')
Python
1 vote311 views1 answer
Robot framework log from python
Python
0 vote260 views1 answer
Static Assets in Django
Python