Question

I’m trying to figure out what’s wrong with my code. Could anyone fix it?

def main():
   fname = input("Enter filename:")
   infile = open(fname, "r")
   SD()

def SD():
  b= []
  a = 5.0 
  r = len(b) 
  for n in range(r-1):
      b.append((r[n] -a)**2)
  m = (float(b)/r)**0.5
  print("The standard deviation is", m)
main()

Answer 1

You have a handful of errors:

def SD():

  # b is empty
  b= []
  a = 5.0 

  #this will always be 0
  r = len(b) 

  # range(r-1) == [] because it is range(-1)
  # whole loop is skipped
  for n in range(r-1):
      b.append((r[n] -a)**2)

  # float(b) should throw an error, maybe sum(b) ?
  m = (float(b)/r)**0.5
  print("The standard deviation is", m)
main()

b is a list; you can’t cast a list into a float.

perhaps you want to pass an array to SD()? You should read() the files contents and then perhaps split() that into an array and pass it to SD() as an argument (where you’ll call int() on them.)