Python – Writing a dict to txt file and reading it back

python

I am trying to write a dictionary to a txt file. Then read the dict values by typing the keys with raw_input. I feel like I am just missing one step but I have been looking for a while now.

I get this error

File "name.py", line 24, in reading
    print whip[name]
TypeError: string indices must be integers, not str

My code:

#!/usr/bin/env python
from sys import exit

class Person(object):
    def __init__(self):
        self.name = ""
        self.address = ""
        self.phone = ""
        self.age = ""
        self.whip = {}

    def writing(self):
        self.whip[p.name] = p.age, p.address, p.phone
        target = open('deed.txt', 'a')
        target.write(str(self.whip))
        print self.whip

    def reading(self):
        self.whip = open('deed.txt', 'r').read()
        name = raw_input("> ")
        if name in self.whip:
            print self.whip[name]

p = Person()

while True:
    print "Type:\n\t*read to read data base\n\t*write to write to data base\n\t*exit to exit"
    action = raw_input("\n> ")
    if "write" in action:
        p.name = raw_input("Name?\n> ")
        p.phone = raw_input("Phone Number?\n> ")
        p.age = raw_input("Age?\n> ")
        p.address = raw_input("Address?\n>")
        p.writing()
    elif "read" in action:
        p.reading()
    elif "exit" in action:
        exit(0)

Best Answer

Have you tried the json module? JSON format is very similar to python dictionary. And it's human readable/writable:

>>> import json
>>> d = {"one":1, "two":2}
>>> json.dump(d, open("text.txt",'w'))

This code dumps to a text file

$ cat text.txt 
{"two": 2, "one": 1}

Also you can load from a JSON file:

>>> d2 = json.load(open("text.txt"))
>>> print d2
{u'two': 2, u'one': 1}

Related Solutions

Python – Unicode (UTF-8) reading and writing to files in Python

Rather than mess with the encode and decode methods I find it easier to specify the encoding when opening the file. The io module (added in Python 2.6) provides an io.open function, which has an encoding parameter.

Use the open method from the io module.

>>>import io
>>>f = io.open("test", mode="r", encoding="utf-8")

Then after calling f's read() function, an encoded Unicode object is returned.

>>>f.read()
u'Capit\xe1l\n\n'

Note that in Python 3, the io.open function is an alias for the built-in open function. The built-in open function only supports the encoding argument in Python 3, not Python 2.

Edit: Previously this answer recommended the codecs module. The codecs module can cause problems when mixing read() and readline(), so this answer now recommends the io module instead.

Use the open method from the codecs module.

>>>import codecs
>>>f = codecs.open("test", "r", "utf-8")

Then after calling f's read() function, an encoded Unicode object is returned.

>>>f.read()
u'Capit\xe1l\n\n'

If you know the encoding of a file, using the codecs package is going to be much less confusing.

See http://docs.python.org/library/codecs.html#codecs.open

Python – Writing a list to a file with Python

You can use a loop:

with open('your_file.txt', 'w') as f:
    for item in my_list:
        f.write("%s\n" % item)

In Python 2, you can also use

with open('your_file.txt', 'w') as f:
    for item in my_list:
        print >> f, item

If you're keen on a single function call, at least remove the square brackets [], so that the strings to be printed get made one at a time (a genexp rather than a listcomp) -- no reason to take up all the memory required to materialize the whole list of strings.

Best Answer

Related Solutions

Python – Unicode (UTF-8) reading and writing to files in Python

Python – Writing a list to a file with Python

Related Topic