使用python从文件读取数据

Question

can't read all data from file useing Python

inside test.txt there is :

{'God': {u'user1@localhost': {}, u'user2@localhost': {}, u'user3@localhost': {}}}

and the code is :

# coding: utf-8

def read_file(filename):
    data=None
    try:
        fp = file(filename)
        data = fp.read()
        fp.close()
    except: pass
    return data

def read():
    file = 'test.txt'
    db = eval(read_file(file))
    if "God" in db:
        for x in db["God"]:
            data = x
            #print(x) $$ it'll print all data True but I do not need it, I will put instructions inside and I do not need to be repeated.
        print(x) # $$ print just 1 data from file

try: read()
except: pass

how can I let it to read all data from file

thx.

Answer 1

To read all data from a text file just use read method of a file object, eg

with open('test.txt','r') as f:
    file_content = f.read()

Answer 2

instead of using file() try open() in fact you should get in the habit of that. Developers are directed to use open() instead of file() in all cases.

Answer 3

1. Read File using with and open method.
2. eval file content to get content into dictionary format.
3. Use has_key to check God key is present or not. [use in 'has_key()' or 'in'?
4. Use 'keys() method to get all keys of God value` dictionary.
5. use 'join()` string method

code:

def readFile(filepath):
    with open(filepath, "rb") as fp:
        data = fp.read()         
    db = eval(data)
    if "God" in db:
        godkeys= db["God"].keys()
        print "godkeys:-", godkeys
        print "Data:", ','.join(godkeys)

filepath = '/home/infogrid/Desktop/input1.txt'
readFile(filepath)

output:

$ python  workspace/vtestproject/study/test.py
godkeys:- [u'user3@localhost', u'user2@localhost', u'user1@localhost']
Data: user3@localhost,user2@localhost,user1@localhost

Answer 4

db = eval(read_file(file))

db is a dictionary. Dictionary is collection of many pairs of key and value. To check if some key is in dict, we should use keys() function as below:

if "God" in db.keys():

Also, to get all data in dict, we just use items() to get pair of key and value.

for key, value in db["God"].items():
    print "Key", key
    print "Value", value