"Statement has no effect"

[birdieman]

I am still a beginner, but I want to read a file once, do processing, then write to the file.  the read code is:

f = open("test3.txt", "w")
with open("test3.txt", "r") as opened_file:
    for line in opened_file:
        MS, StartYear, YourStartAge, HerStartAge,
        Exempt, BFedItmDed, FedItmDedYrs, State, LivExp,
        Inflation, Inf1, Inf2, Inf3, Inf4, Inf5, Inf6, Inf7, Inf8, Inf9, Inf10,
        TESTPcnt, TESTYr, TFISTPcnt, TFISTYr, TFESTPcnt, TFESTYr,
        TFFISTPcnt, TFFISTYr, TDESTPcnt, TDESTYr, TDFISTPcnt, TDFISTYr,
        BTE, BTFI, BTC, TERtn, TFIRtn, TCRtn, BTFE, BTFFI, BTFC, TFERtn,
        TFFIRtn, TFCRtn, BTDE, BTDFI, BTDC, TDERtn, TDFIRtn, TDCRtn,
        YourJob, SpJob, YourRetInc, SpRetInc, YourSSInc62,
        YourSSIncFRA, YourSSInc70, SpSSInc62, SpSSIncFRA, SpSSInc70,
        YourRetAge, SpRetAge, YouBgnRetIncAge, SpBgnRetIncAge,
        YouSSStartAge, SpSSStartAge, IraStartAge, IraEndAge, IraRequest = line.split()

to write the file, I have this code:

f.write('{} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {}'
        '{} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {}'
        '{} {} {} {} {} {} {} {} {} {} {} {} {}'
        .format(MS, StartYear, YourStartAge, HerStartAge,
                Exempt, BFedItmDed, FedItmDedYrs, State, LivExp,
                Inflation, Inf1, Inf2, Inf3, Inf4, Inf5, Inf6, Inf7, Inf8, Inf9, Inf10,
                TESTPcnt, TESTYr, TFISTPcnt, TFISTYr, TFESTPcnt, TFESTYr,
                TFFISTPcnt, TFFISTYr, TDESTPcnt, TDESTYr, TDFISTPcnt, TDFISTYr,
                BTE, BTFI, BTC, TERtn, TFIRtn, TCRtn, BTFE, BTFFI, BTFC, TFERtn,
                TFFIRtn, TFCRtn, BTDE, BTDFI, BTDC, TDERtn, TDFIRtn, TDCRtn,
                YourJob, SpJob, YourRetInc, SpRetInc, YourSSInc62,
                YourSSIncFRA, YourSSInc70, SpSSInc62, SpSSIncFRA, SpSSInc70,
                YourRetAge, SpRetAge, YouBgnRetIncAge, SpBgnRetIncAge,
                YouSSStartAge, SpSSStartAge, IraStartAge, IraEndAge, IraRequest))
f.close()

My PyCharm IDE says the "read" code (highlighting the variables) has no effect. 

What is wrong with the read code?

[Mekire]

You need to go back to string formatting; nevermind file read/writing. Don't do this.
Both the unpacking and formatting code are horrendous.

[birdieman]

Thanks for your response, but I am still too new to python to know what your answer means. I had no other idea how to read and write variables to a file.

[metulburr]

I would suggest to use JSON rather than relying on line position and splitting delimiters. Which in python is basically a dictionary.

EDIT:
here is an example. Note: this class is using staticmethod to avoid the use of an object, and intends to only handle 1 database due to hardcoding the name in it. 

test.py

import sys
import os
import json

class DB:
    dirname = 'save'
    if not os.path.exists(dirname):
        os.mkdir(dirname)
    path = os.path.join(dirname, 'database{}'.format(sys.version.split()[0]))

    @staticmethod
    def load():
        data = open(DB.path)
        obj = json.load(data)
        data.close()
        return obj
    @staticmethod
    def save(obj):
        f = open(DB.path, 'w')
        f.write(json.dumps(obj))
        f.close()

Output:
metulburr@ubuntu:~$ cd save
bash: cd: save: No such file or directory

Output:
metulburr@ubuntu:~$ python
Python 2.7.12 (default, Nov 19 2016, 06:48:10) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from test import DB
>>> data = {
... 
...     'entry1':1,
...     'entry2':2
... }
>>> data
{'entry2': 2, 'entry1': 1}
>>> DB.save(data)
>>> exit()

Output:
metulburr@ubuntu:~$ cat save/database2.7.12 

{"entry2": 2, "entry1": 1}

Output:
metulburr@ubuntu:~$ python
Python 2.7.12 (default, Nov 19 2016, 06:48:10) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from test import DB
>>> d = DB.load()
>>> d
{u'entry2': 2, u'entry1': 1}

[Mekire]

Well, I would rather see something like this (untested):

Hide/Show

FIELDS = ["MS", "StartYear", "YourStartAge", "HerStartAge", "Exempt",
    "BFedItmDed", "FedItmDedYrs", "State", "LivExp", "Inflation", "Inf1",
    "Inf2", "Inf3", "Inf4", "Inf5", "Inf6", "Inf7", "Inf8", "Inf9", "Inf10",
    "TESTPcnt", "TESTYr", "TFISTPcnt", "TFISTYr", "TFESTPcnt", "TFESTYr",
    "TFFISTPcnt", "TFFISTYr", "TDESTPcnt", "TDESTYr", "TDFISTPcnt", "TDFISTYr",
    "BTE", "BTFI", "BTC", "TERtn", "TFIRtn", "TCRtn", "BTFE", "BTFFI", "BTFC",
    "TFERtn", "TFFIRtn", "TFCRtn", "BTDE", "BTDFI", "BTDC", "TDERtn", "TDFIRtn",
    "TDCRtn", "YourJob", "SpJob", "YourRetInc", "SpRetInc", "YourSSInc62",
    "YourSSIncFRA", "YourSSInc70", "SpSSInc62", "SpSSIncFRA", "SpSSInc70",
    "YourRetAge", "SpRetAge", "YouBgnRetIncAge", "SpBgnRetIncAge",
    "YouSSStartAge", "SpSSStartAge", "IraStartAge", "IraEndAge", "IraRequest"]


with open("in_file.txt") as in_file, open("out_file.txt" 'w') as out_file:
    for line in in_file:
        data = {key: val for (key, value) in zip(FIELDS, line.strip().split()}
        # do something with data presumably converting some of them to
        # the needed data types for calculation.
        out_file.write(" ".join(data[key] for key in FIELDS) + "\n")

But really as Metul said you should, at bare minimum, probably be using JSON. Honestly it kinda looks like you should be using an actual database.

[snippsat]

There are also easy solution for fast storage as i show in tutorial with dataset.
It's just a couple of lines connet(make database),
now trow a Python dictionary into the table and we are finish. 
Have now a fully working database,that also can be outputted as json.

[birdieman]

Thanks to all for responding.

Metalburr-

I still have a lot to learn regarding your example.

When it says "entry1:1" I assume the "entry1" (the key) is my variable name, and I assume the "1" is the value of that variable. Is that correct?

How/where do I load the database for the first time, like {MS: M, StartYear: 2017, ........}

[metulburr]

When it says "entry1:1" I assume the "entry1" (the key) is my variable name, and I assume the "1" is the value of that variable. Is that correct?

Yes

How/where do I load the database for the first time, like {MS: M, StartYear: 2017, ........}

The easiest method would be to write it in JSON (dictionary) format in the first place.

[Kebap]

Do you create this file yourself? Can you change the format?

[birdieman]

yes, i can change the format. After reading Metulburr, and if I understand dictionaries correctly, I would have to refer to my variables like xyz["StartYear"] and I do not want to do that -- too long and cumbersome. I just want to use my variables by their name, like StartYear (if possible).

Do you have another suggestion?