Question

this is a python3 question

every_second_line

Complete the following function according to its docstring description.

Notes:

report is a file open for reading, not a string representing the name of a file.

the method str.strip() may come in handy!

def every_second_line(report):
""" (Open File for reading) -> list of str
  
Return a list containing every second line (with leading and trailing
whitespace removed) in report, starting with the first line.
"""

I really got stuck on this question:( could someone please explain to me? thanks in advance!

Answer 1

Hi,

I didn't get exactly what you're asking for, though I guess you need to iterate over every second line and write it in Python 3.

Well, all you need to do is add report.readLine() inside your for loop, that writes lines sequentially.

Assuming your code has even number of lines, use below code -

def every_second_line(report):
list=[]
for line in report:
   list.append(line.strip)
   report.readLine()
return list

If your code has odd number of lines, use the following piece of code. This will add the optional argument (None) to the next method, which tells the compiler to ignore all errors, like StopIteration or EOFError.
Note that next(report) is used instead of report.readLine() to iterate over anything and everything, not just limiting your iteration to files.

def every_second_line(report):
list=[]
for line in report:
   list.append(line.strip)
   next(report, None)
return list