Python - read from file skip lines starts with #

Question

Try to read file and make a dictionary from lines, skippipng lines starts with # symbol

file example:

param1=val1
# here is comment

My function:

def readFromFile(name):
    config = {}
    with open(name, "r") as f:         
        for line in f.readlines():
            li=line.lstrip()
            if not li.startswith("#"):
                config[line.split('=')[0]] = line.split('=')[1].strip()
    return config

I get list index out of range error

But! if i try to skip lines starts with, for example, symbol "h" - function works well...

Answer 1

Try with:

def readFromFile(name):
    config = {}
    with open(name, "r") as f:         
        for line in f.readlines():
            li = line.lstrip()
            if not li.startswith("#") and '=' in li:
                key, value = line.split('=', 1)
                config[key] = value.strip()
    return config

You maybe have a blank line which breaks your split()

Answer 2

Your code works just fine, except for lines that neither start with a # nor contain a = character. Usually, those are empty lines.

Test for the = character before splitting:

def readFromFile(name):
    config = {}
    with open(name, "r") as f:         
        for line in f.readlines():
            li=line.lstrip()
            if not li.startswith("#") and '=' in li:
                config[line.split('=')[0]] = line.split('=')[1].strip()
    return config

You can simplify the code and make it a dict comprehension:

def readFromFile(name):
    with open(name, "r") as f:         
        return {k: v 
            for line in f 
            for (k, v) in (line.strip().split('=', 1),)
            if '=' in line.strip() and line[:1] != '#'}

You can loop over f (a file object) directly ; no need to read all lines into memory using f.readlines() first. I used .split('=', 1) to only split on the equals sign once .

Answer 3

You can return a dictionary directly:

 def readFromFile(name):
     with open(name) as f:
         return { line.split('=')[0]:line.split('=')[1].strip() for line in f \
                  if not line.startswith('#' and '=' in line }