Creating objects from parsed file

Question

I'm newbie in Python but I want to know some tricks to make my code look cute. I know that syntax of Python allows to do this, but I don't know how. Suppose I have file with lines of format "x y z" and I want to parse it and make some objects. Now code looks like this:

class Point(object):
 def __init__(self, x, y, z):
 self.x = x;
 self.y = y;
 self.z = z;
...
def load_file(file_path):
 points = [];
 with open(file_path, "r") as input_file:
 for line in input_file:
 str_point = line.split();
 x = float(str_point[0]);
 y = float(str_point[1]);
 z = float(str_point[2]);
 points.append(Point(x, y, z));
 return points;

Is there any way to make this code simpler?

Answer 1

Instead of parsing x, y, z one by one, you can use a list comprehension, and pass the whole thing directly to the the constructor of Point using * like this:

def load_file(file_path):
 objects = []
 with open(file_path) as input_file:
 for line in input_file:
 obj = Point(*[float(x) for x in line.split()])
 objects.append(obj)
 return objects

I dropped the "r" in open(..., "r"), as that's the default anyway. Even more importantly, ; are not required to end statements in Python, and they are just noise in the posted code.

It would be even cuter to use a generator pattern instead:

def load_file(file_path):
 with open(file_path) as input_file:
 for line in input_file:
 yield Point(*[float(x) for x in line.split()])

You could iterate over this to do something with the objects, for example:

for obj in load_file(file_path):
 # do something ...

Or you could load all into a list using a list comprehension:

objects = [x for x in load_file(file_path)]