Creating a .txt file from a dictionary

Question

I have a .txt file like this:

ID - NAME - LASTNAME - USER - PASSWORD

0001 - Oliver - Jackson - olson - pass123

0002 - Samuel - Depp - samuel - pass321

Then, I created a dictionary from the .txt file:

{'0001': ['Oliver', 'Jackson', 'olson', 'pass123'], '0002': ['Samuel', 'Depp', 'samuel', 'pass321']}

Now, if someone wants to change one of the values inside the dictionary it's easy, but I need to overwrite the .txt file with such new values, something like this (no luck until now):

{'0001': ['Oliver', 'Jackson', 'newlog01', 'newpass01'], '0002': ['Samuel', 'Depp', 'samuel', 'pass321']}

0001 - Oliver - Jackson - newlog01 - newpass01

.

.

.

Thanks

Answer 1

This solution will work for your current system, but it's recommended you don't store this data in your own custom format. You should simply use the build in json library.

import json

input = '{\"0001\": [\"Oliver\", \"Jackson\", \"newlog01\", \"newpass01\"], \"0002\": [\"Samuel\", \"Depp\", \"samuel\", \"pass321\"]}'

data = dict()

try:
    data = json.loads(input)
except ValueError as e:
    print e

print 'ID - NAME - LASTNAME - USER - PASSWORD'
for key in sorted(data.keys()):
    print ' - '.join([key] + data[key])

Output:

ID - NAME - LASTNAME - USER - PASSWORD
0001 - Oliver - Jackson - newlog01 - newpass01
0002 - Samuel - Depp - samuel - pass321

Answer 2

You'll have to replace the entire file with the new contents

def read_file(filename):
    data = {}
    with open(filename, 'r') as fhd:
        for line in fhd:
            tokens = [token.strip() for token in line.split('-')]
            data[tokens[0]] = tokens[1:]
    return data


def write_file(filename, data):
    with open(filename, 'w') as fhd:
        for key in sorted(data.keys()):
            fhd.write('{} - {}\n'.format(key, ' - '.join(data[key])))

And use it as:

if __name__ == '__main__':
    filename = 'test.dat'
    data = read_file(filename)
    data['0001'][1] = 'changed'
    write_file(filename, data)

There is no way around it. Data in disk is stored serially.

Answer 3

One quick way to do this is just create a serialization function that given one of your specially formatted dictionaries, will return it as a string encoded in your custom format. Then just write that out to the original file and you're golden.

eg

import os

def encode(data):
    header = "ID - NAME - LASTNAME - USER - PASSWORD"
    lines = [' - '.join([key] + values) for (key, values) in data.iteritems()]
    return (os.linesep+os.linesep).join([header] + lines)

Then you can write it back out again with something like:

with open('data.txt','w') as f:
    f.write(encode(d) + os.linesep)

Answer 4

Firstly you can use the json library , it's very good for your project. if you don't want to use json file and you need to change some datas from txt file :

import os 
new_txtfile=open("newfile.txt","w")
def get_the_datas_from_your_txtfile():
    #on this function you can do change as you want with dictionary
    # and now whrite the new dictionary to new_txtfile 
get_the_datas_from_your_txtfile()
your_txtfile.close()
new_txtfile.close() #her closing files 

os.remove("your_txtfile.txr")
os.renames("new_txtfile.txt","your_txtfile.txt")
#on thir we have removed the old file and changed the
#new files name to old files name 

Answer 5

This will do it about as tight as possible.

d_map = {'0001': ['Oliver', 'Jackson', 'olson', 'pass123'], '0002': ['Samuel', 'Depp', 'samuel', 'pass321']}
rv_str = ''
for key in d_map.keys():
    rv_str += key + ' - ' + ' - '.join(d_map[key]) + '\n'
with open('file.txt', 'w') as file_d:
    file_d.write(rv_str)