Convert list to a string with double quotes For an external application I need to send a command as a string, like this: 

["START", "1", "2", "3", "4", "STOP"]

Note the double quotes!

I create this command with the following function:

def create_command(amount):
    command = ["START"]
    list = create_list(amount)
    command += list
    command += ["STOP"]
    command = str(command ) 
    command = command.replace("\'", "\"")
    return command


And I create a list from a given number with the following function:

def create_list(data):
    list = []
    data = str(data)
    for letter in data:
        list.append(letter)
    return list


Is the a way to make both functions more pythonic and not so straightforward?  I don't really like them now, they look a bit clumpsy and I think there must be a better way do the thing.
create_list is building a list of all the items in the string form of data. And so you can change it to:

def create_list(data):
    return list(str(data))


I find it easier to read create_command if you merge some of the lines together:

def create_command(amount):
    command = ["START"] + create_list(amount) + ["STOP"]
    return str(command).replace("\'", "\"")


And so you can merge the above two changes together:

def create_command(amount):
    command = ["START"] + list(str(amount)) + ["STOP"]
    return str(command).replace("\'", "\"")




Expanding further, rather than using str.replace you can use json.dumps to format the list. This has the benefit that it will escape ' and " characters for you, which your code doesn't correctly handle. (Thanks Mathias)

import json


def create_command(amount):
    command = ["START"] + list(str(amount)) + ["STOP"]
    return json.dumps(command)