Get specific section in text file Python and save to dict UnboudLocalError

Question

I am working on a flask server which accepts .log file POSTS (basically just a text file). These files contain data resulting from invoking the command line smartctl command

smartctl -a /dev/sda

I got it working, but I used the lines numbers in the file hardcoded, this isn't optimal, as the amount of lines could differ with different hard disks. The following is part of my working code:

def parse_line(line): # For colons; device info
    splitted = line.split(':')
    return splitted[0], splitted[1].strip()

file_body = request.form['smartdata']

lines = file_body.split("\n")

my_data = {}  # Empty dictionary object
    for line in lines[4:22]: # Device info
        if ":" in line:
            if line.startswith("Device is:"): # Not necessary
                pass
            else:
                key, value = parse_line(line)

        my_data[key] = value

I tried searching for section headers in the .log file instead to determine what kind of splitting I should be doing;

def parse_line(line): # For colons; device info
splitted = line.split(':')
return splitted[0], splitted[1].strip()

copy = False
    device_info = {}

    for line in lines:
        if line.strip() == "=== START OF INFORMATION SECTION ===": #start of device info
            copy = True
        if line.strip() == "=== START OF READ SMART DATA SECTION ===": #start of smart data section, end of device info
            copy = False
        if copy: #if iterating lines and passed the information section header, true and sends said line to the parse_line method
            key, value = parse_line(line)

        device_info[key] = value

However, I am getting the following error:

UnboundLocalError: local variable 'value' referenced before assignment

I don't quite get how I could be getting this error from the

device_info[key] = value

As I am basically doing the same thing as I was before.

Answer 1

Shouldn't the device_info[key] = value line be in the same block where value get's assigned?

def parse_line(line): # For colons; device info
splitted = line.split(':')
return splitted[0], splitted[1].strip()

copy = False
    device_info = {}

    for line in lines:
        if line.strip() == "=== START OF INFORMATION SECTION ===": #start of device info
            copy = True
        if line.strip() == "=== START OF READ SMART DATA SECTION ===": #start of smart data section, end of device info
            copy = False
        if copy: #if iterating lines and passed the information section header, true and sends said line to the parse_line method
            key, value = parse_line(line)
            # Now value will always be defined.
            device_info[key] = value

Answer 2

As some said, device_info should be indented correctly. I had to add a check to see if ":" is in line and only then assign a value to my dict, as my parse_line method is expecting a colon to split lines. The following code works.

def parse_line(line): # For colons; device info
splitted = line.split(':')
return splitted[0], splitted[1].strip()


    copy = False
    device_info = {}

    for line in lines:
        if line.strip() == "=== START OF INFORMATION SECTION ===":
            copy = True
        if line.strip() == "=== START OF READ SMART DATA SECTION ===":
            copy = False
        if copy and ":" in line: # Make sure : is in line to use parse_line
            key, value = parse_line(line)
            # Value will be defined
            device_info[key] = value