Question

My program is supposed to read a text document with a bunch of numbers and make a list of only the positive numbers. I can’t convert the strings from the text document to a float so i can’t determine if they are postive.

I linked a screenshot because my copy paste is buggy.

https://i.stack.imgur.com/L1Z7z.png

Without the number = float(number) , I get ['3.7', '-22', '3500', '38', '-11.993', '2200', '-1', '3400', '3400', '-3400', '-22', '12', '11', '10', '9.0']

Answer 1

You can translate that list into floats easily:

>>> nums = ['3.7', '-22', '3500', '38', '-11.993', '2200', '-1', '3400', '3400', '-3400', '-22', '12', '11', '10', '9.0']
>>> map(float, nums)
[3.7, -22.0, 3500.0, 38.0, -11.993, 2200.0, -1.0, 3400.0, 3400.0, -3400.0, -22.0, 12.0, 11.0, 10.0, 9.0]

But the problem seems to be that the lines in your file don’t contain individual floats. When you call float(number), number is a line from the file, which (from the error) appears to contain three space-separated numbers “3.7 -22 3500”.

What you need is to call the float function after splitting:

for line in f:
  for numberString in line.split()
    number = float(numberString)
    if(number > 0)
      numbers.append(number)

Or, more functionally:

for line in f:
  numbers.extend([n for n in map(float, line.split()) if n > 0])