Appending more than one element to the list

Question

I want to add to the empty list lines from the file but only one is appending. When I use extend, every single letter is appending. I want that every line is the new element in the list. If i use for - if method printed is everything but appended only the last one.

If i use for - if method printed is everything but appended only the last one.

with open ("sesja1_1101_1.19o", "r", encoding = "UTF-8") as file:
    isIn = file.readlines()
    for line in isIn:
    elif "PRN / # OF OBS" in line:
            line = line.replace("\n", "")           
            line = line.replace("PRN / # OF OBS", "")
            line = line.lstrip()
            line = line.rstrip()
            sattelites = []
            sattelites.append(line)

            print (line)

result:

runfile('C:/Users/HP/Desktop/mgr/mgr.py', wdir='C:/Users/HP/Desktop/mgr')
G05   729     0   688   400   400
G07   622     0   595   307   307
G08   486     0   455   259   259
G11   220     0   194    83    83
G13  1149     0  1149  1149  1149
G15   929     0   916   851   851
G17   378     0   365   261   261
G20    59     0    41     0     0
G24   510     0   495   465   465
G28  1149     0  1149  1149  1149
G30  1149     0  1149  1149  1149
R01   311   308   310   582   279
R07  1148  1148  1148  2294  1148
R08  1149  1149  1149  2298  1149
R09  1149  1149  1149  2298  1149
R10  1149  1149  1149  2298  1149
R11   357   357   357   712   355
R16   250   232   236   454   230
R17     6     1     4     1     0
R18  1113  1095  1112  2164  1089
R19   234   227   231   449   226


sattelites
Out[16]: ['R19   234   227   231   449   226']

Answer 1

as commented above, you should initialize your list outside of the loop. and for some unknown reason you're opening an 'if' condition with 'else'...

example to try..

sattelites = []
with open ("open_this", "r", encoding = "UTF-8") as file:
    isIn = file.readlines()
    for line in isIn:
        if "this_exists" in line: # <-- change 'elif' to 'if'
            new_line = line
            new_line = new_line.replace('replace/remove').lstrip('some').rstrip('stuff')
            sattelites.append(new_line)
            print(new_line)