Splitting lines ang grouping three at once

[samsonite]

What I've done, up to now, is successful only for the first group of short.txt database, while my goal is to have some drifts on adjusting iteratively the line tle= data[0]+'\n'+data[1]+'\n'+data[2]+'\n' in order to complete the whole file scanning.
Thx in advance

# --- line6.py ------
with open ("short.txt", "r") as myfile:
    data = myfile.read().splitlines()
tle= data[0]+'\n'+data[1]+'\n'+data[2]+'\n'
print(tle)
#------ OUTPUT ----------    
'''
FALCON 9 DEB
1 44298U 19029BR  19167.86418532  .00001313  00000-0  38063-4 0  9991
2 44298  53.0043  62.2948 0004912  13.4119 346.7015 15.43512957  4901
'''

short.txt

Output:
FALCON 9 DEB            
1 44298U 19029BR  19167.86418532  .00001313  00000-0  38063-4 0  9991
2 44298  53.0043  62.2948 0004912  13.4119 346.7015 15.43512957  4901
STARLINK AB             
1 44260U 19029AB  19157.99245370  .01269439  00000-0  29305-1 0  9993
2 44260  53.0001 109.7412 0006821  81.1213 255.2409 15.39387046  2245
STARLINK E              
1 44239U 19029E   19167.13356954 -.00013522  00000-0 -91175-3 0  9994
2 44239  53.0083  69.0416 0002637 113.5217 246.6049 15.05529924  3542
STARLINK P              
1 44248U 19029P   19167.86126092 -.00617922  00000-0 -42907-1 0  9993
2 44248  52.9974  64.8224 0004816  42.9633 317.1731 15.07410453  3682
STARLINK D              
1 44238U 19029D   19167.85872376 -.00444761  00000-0 -30673-1 0  9990
2 44238  52.9982  64.8538 0002160  82.0309 278.0925 15.07669053  2123
STARLINK H              
1 44242U 19029H   19167.72360443 -.01130229  00000-0 -86918-1 0  9993
2 44242  52.9937  65.5606 0008561  56.4128 303.7676 15.04350216  3717

[ichabod801]

Note that data[index:(index + 3)] gives the three item list starting at index. You can make a simple loop with range(0, len(data), 3) that gets every three item slice of the list.

[samsonite]

Error erupts

# --- line6bis.py ------
with open ("short.txt", "r") as myfile:
    data[index:(index + 3)] = myfile.read().splitlines()
tle= data [range(0, len(data), 3)]
print(tle)

Error:
C:\Training>python line6bis.py
Traceback (most recent call last):
  File "line6bis.py", line 3, in <module>
    data[index:(index + 3)] = myfile.read().splitlines()
NameError: name 'data' is not defined

[ichabod801]

First of all, you didn't make the loop I mentioned, which would come after the file is read. Before the loop you initialize an empty list, and then in the loop you append the slide I mentioned to the new list.

[samsonite]

Last tentative ... hoping someone helps by writing the solution. Thank you, forum!

# --- line6ter.py ------
with open ("short.txt", "r") as myfile:
	data = ""	
index=0
data[index:(index + 3)] = myfile.read().splitlines()
tle= data [range(0, len(data), 3)]
print(tle)

Error:
C:\Training>python line6ter.py
Traceback (most recent call last):
  File "line6ter.py", line 7, in <module>
    data[index:(index + 3)] = myfile.read().splitlines()
ValueError: I/O operation on closed file.

[ichabod801]

Hoping someone will read one of my posts some day.