Python Forum

say i have a list
[1,2,3,4,5,6,7]

and id like to print, 3,4,5 then 2,3,4,5,6 finally 1,2,3,4,5,6,7
using a for loop, and a slice value within its body is it possible to add to a set slice value?

as this doesn't work i will present it as pseudo code as an example to possibly better illustrate.

inv=[1,2,3,4,5,6,7]

for i in range(0,3,1):
add=(inv[3-1:4+1])

print (add)

The [3-1:4+1] being the pseudo part of the code for now as it doesn't increment on each pass. It only changes the value of the slice the one time.

You should just try these things and see if they work.

Output:
>>> x='123456789'
>>> y=x[3-1:3+1]
>>> y
'34'
>>> for a in range(3):
	print(f'x[3-{a}:3+{a}] = "{x[3-a:3+a]}"')

x[3-0:3+0] = ""
x[3-1:3+1] = "34"
x[3-2:3+2] = "2345"
>>> 

I do a lot of testing using the Python console built into IDLE or running python in a shell window. For just trying things like this it is much quicker than writing a program. You also have the advantage of built in interactive help.

Output:
>>> type(x)
<class 'str'>
>>> dir(str)
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']
>>> help(str.replace)
Help on method_descriptor:

replace(self, old, new, count=-1, /)
    Return a copy with all occurrences of substring old replaced by new.
    
      count
        Maximum number of occurrences to replace.
        -1 (the default value) means replace all occurrences.
    
    If the optional argument count is given, only the first count occurrences are
    replaced.

>>> 

You nailed it XD
thank you