How can I "build" a dictionary within a txt file using Python, over time?

I need to take two variables, for example...

some_string = "Hello, World!"

some_float = 3958.8

...then write those two variables to a txt file, as a dictionary.

For the key/value pair, some_string should be the key, and some_float should be the value.

Next time I run the program, some_string and some_float will be different, and will need to get written/added to the same txt file, essentially adding another key/value pair to the now already existing dictionary (txt file).

All I've been able to find is information regarding adding a known dictionary to a txt file, not building one up over time. In my case, I don't know ahead of time what some_string and some_float will be next time I run the program, so I can't pre-build the dictionary and just write it all to the txt file at once.

Any ideas?

CodePudding user response：

You can use open file mode append ('a') to append to the file the new content and update the file that way every time you add a new value. Here's an exemple on how to do it:

def add_dic(key, value):
    with open('dic.txt', mode='a') as fp:
        fp.write(key   " "   str(value)   '\n')


def read_dic():
    dic = {}
    with open('dic.txt', mode='r') as fp:
        for line in fp.readlines():
            words = line.split(' ')
            key = words[0]
            value = float(words[1])
            dic[key] = value

    return dic


some_string = input("string: ")
some_float = float(input("float: "))

add_dic(some_string, some_float)

dic = read_dic()
print(dic)

CodePudding user response：

I am not quite sure whether this what you are looking for but you can use the method explained in this https://link.medium.com/3v2WRRxFYqb it shows how to update the existing lines or create new ones.