Develop Reference

Python How to add nested fields to Yaml file

I need to modify a YAML file and add several fields.I am using the ruamel.yaml package.
First I load the YAML file:
data = yaml.load(file_name)
I can easily add new simple fields, like-
data['prop1'] = "value1"
The problem I face is that I need to add a nested dictionary incorporate with array:
prop2:
prop3:
- prop4:
prop5: "Some title"
prop6: "Some more data"
I tried to define-
record_to_add = dict(prop2 = dict(prop3 = ['prop4']))
This is working, but when I try to add beneath it prop5 it fails-
record_to_add = dict(prop2 = dict(prop3 = ['prop4'= dict(prop5 = "Value")]))
I get
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
What am I doing wrong?

The problem has little to do with ruamel.yaml. This:
['prop4'= dict(prop5 = "Value")]
is invalid Python as a list ([ ]) expects comma separated values. You would need to use something like:
record_to_add = dict(prop2 = dict(prop3 = dict(prop4= [dict(prop5 = "Some title"), dict(prop6='Some more data'),])))
As your program is incomplete I am not sure if you are using the old API or not. Make sure to use
import ruamel.yaml
yaml = ruamel.yaml.YAML()
and not
import ruamel.yaml as yaml

Its because of having ['prop4'= <> ].Instead record_to_add = dict(prop2 = dict(prop3 = [dict(prop4 = dict(prop5 = "Value"))])) should work.
Another alternate would be,
import yaml
data = {
"prop1": {
"prop3":
[{ "prop4":
{
"prop5": "some title",
"prop6": "some more data"
}
}]
}
}
with open(filename, 'w') as outfile:
yaml.dump(data, outfile, default_flow_style=False)

Dictionary from a String with particular structure

I am using python 3 to read this file and convert it to a dictionary.
I have this string from a file and I would like to know how could be possible to create a dictionary from it.
[User]
Date=10/26/2003
Time=09:01:01 AM
User=teodor
UserText=Max Cor
UserTextUnicode=392039n9dj90j32
[System]
Type=Absolute
Dnumber=QS236
Software=1.1.1.2
BuildNr=0923875
Source=LAM
Column=OWKD
[Build]
StageX=12345
Spotter=2
ApertureX=0.0098743
ApertureY=0.2431899
ShiftXYZ=-4.234809e-002
[Text]
Text=Here is the Text files
DataBaseNumber=The database number is 918723
..... (There are more than 1000 lines per file) ...
On the text I have "Name=Something" and then I would like to convert it as follows:
{'Date':'10/26/2003',
'Time':'09:01:01 AM'
'User':'teodor'
'UserText':'Max Cor'
'UserTextUnicode':'392039n9dj90j32'.......}
The word between [ ] can be removed, like [User], [System], [Build], [Text], etc...
In some fields there is only the first part of the string:
[Colors]
Red=
Blue=
Yellow=
DarkBlue=

What you have is an ordinary properties file. You can use this example to read the values into map:
try (InputStream input = new FileInputStream("your_file_path")) {
Properties prop = new Properties();
prop.load(input);
// prop.getProperty("User") == "teodor"
} catch (IOException ex) {
ex.printStackTrace();
}
EDIT:
For Python solution, refer to the answerred question.
You can use configparser to read .ini, or .properties files (format you have).
import configparser
config = configparser.ConfigParser()
config.read('your_file_path')
# config['User'] == {'Date': '10/26/2003', 'Time': '09:01:01 AM'...}
# config['User']['User'] == 'teodor'
# config['System'] == {'Type': 'Abosulte', ...}

Can easily be done in python. Assuming your file is named test.txt.
This will also work for lines with nothing after the = as well as lines with multiple =.
d = {}
with open('test.txt', 'r') as f:
for line in f:
line = line.strip() # Remove any space or newline characters
parts = line.split('=') # Split around the `=`
if len(parts) > 1:
d[parts[0]] = ''.join(parts[1:])
print(d)
Output:
{
"Date": "10/26/2003",
"Time": "09:01:01 AM",
"User": "teodor",
"UserText": "Max Cor",
"UserTextUnicode": "392039n9dj90j32",
"Type": "Absolute",
"Dnumber": "QS236",
"Software": "1.1.1.2",
"BuildNr": "0923875",
"Source": "LAM",
"Column": "OWKD",
"StageX": "12345",
"Spotter": "2",
"ApertureX": "0.0098743",
"ApertureY": "0.2431899",
"ShiftXYZ": "-4.234809e-002",
"Text": "Here is the Text files",
"DataBaseNumber": "The database number is 918723"
}

I would suggest to do some cleaning to get rid of the [] lines.
After that you can split those lines by the "=" separator and then convert it to a dictionary.

Editing a JSON file with new information in Python

I'm trying to edit a meta file with new information generated with a python script and don't want to just append the information with a new JSON object, but rather update the read information.
As input I have something like this:
{
"foo1": [
{
"bar1": 0,
"bar2": 1337
},
...
}
So far my code reads the information and stores it in a dictionary. After that the information in this file is deleted and replaced with the updated dictionary. The Code is as shown below:
...
outputData = {"foo2": [{"bar3": True, "bar4": 123}]}
with open(metaFile, 'r+') as f:
metaData = json.load(f)
f.seek(0)
f.truncate()
metaData.update(outputData)
f.write(json.dumps(metaData, indent=2))
f.close()
...
As a result this comes out as expected:
{
"foo1": [
{
"bar1": 0,
"bar2": 1337
}
],
"foo2":[
{
"bar3": true,
"bar4": 123
}
]
}
Now to my exact question, is it possible to edit the file in such a way, that the content in the file doesn't get deleted at first and written again? Because if something happens with the metaData after the initialization, the information is just gone.
Changing the 'r+' argument to 'w+' (+ is optional) will create a new file instead reading from it first and the whole data is gone at this point. With 'a' the outputData cannot be updated and then added, because it would rewrite the already given information. Without updating the metaData it will just create a new object and that's not what I had in mind.

In your case, if you are sure the file size after your changes will always be equal or bigger in size then what's currently in the file, you can call f.write(data) directly.
This way, you don't have to truncate (and lose) the file before writing it.
Also, when you open a file using the with syntax, it will be automatically closed once the with block ends.
In the end you code would look something like this:
outputData = {"foo2": [{"bar3": True, "bar4": 123}]}
with open(metaFile, 'r+') as f:
metaData = json.load(f)
f.seek(0)
metaData.update(outputData)
f.write(json.dumps(metaData, indent=2))
# rest of your code with the normal identation level

You can code as follows, or use MongoDB alternatively.
outputData = {"foo2": [{"bar3": True, "bar4": 123}]}
with open(metaFile, 'r+') as fp:
origin = fp.read()
target = json.dumps(dict(json.loads(origin), **outputData), indent=2)
index = [i for i, (a, b) in enumerate(zip(origin, target)) if a != b][0]
fp.seek(index)
fp.truncate()
fp.write(target[index:])
fp.close()

Read text file and dump to json object

I am doing a task in python (learning phase) wherein i have a text file with list of ip's eg:
10.8.9.0
10.7.8.7
10.4.5.6 and so on. Each on one line , one below another.
I have to read its contents and create its json as [{"ip":"10.8.9.0"},{"ip":"10.7.8.7"}..]
Code:
with open("filename.txt") as file:
content = [x.strip('\n') for x in file.readlines()]
print content
print "content",type(content)
content_json=json.dumps(content)
print content_json
print type(content_json)
The output of content is ['ip adrress1','ip address2'] which is a list.
When i dump the list in content_json the type shown is "Str" .
However i need it as json
My concern is - my further task is to validate ip and add a item in existing json stating {"status":"valid/invalid"}.
I dnt know how to do that as the type of my json is showing str.
Kindly let me knw how to proceed and add status for every ip in existing json.
Also i wish to know why is the type of the json i dumped my list with is being showed as str.
The desired output should be
[
{
"ip":"10.8.9.0",
"status":"valid"
},
{
"ip":"10.7.8.A",
"status":"invalid"
}, ..so on
]

First thing: The result is a list because you're building a list with
[x.strip('\n') for x in file.readlines()]. In case you're not sure that means: Take every line x in file, remove the \n character from it and then build a list of those results. You want something like [{"ip":x.strip('\n')} for x in file.readlines()].
Now, the function json.dumps takes a Python object and attempts to create a JSON representation of it. That representation is serialized as a string so if you ask for the type of content_json that's what you'll get.

You have to make the distinction between a python list/dictionary and a JSON string.
This
>>> with open('input.txt') as inp:
... result = [dict(ip=ip.strip()) for ip in inp]
...
>>> result
[{'ip': '10.8.9.0'}, {'ip': '10.7.8.7'}, {'ip': '10.4.5.6'}]
will give you a list of dictionaries that is easy to mutate. When you are done with it, you can dump it as a JSON string:
>>> result[1]['status'] = 'valid'
>>> result
[{'ip': '10.8.9.0'}, {'status': 'valid', 'ip': '10.7.8.7'}, {'ip': '10.4.5.6'}]
>>> json.dumps(result)
'[{"ip": "10.8.9.0"}, {"status": "valid", "ip": "10.7.8.7"}, {"ip": "10.4.5.6"}]'

You should supply key:value properly for the dump. Putting just the value alone would store it as String
Refer this :
https://docs.python.org/2/library/json.html

Maybe something like this?
import json
import socket
result = list()
with open("filename.txt") as file:
for line in file:
ip = line.strip()
try:
socket.inet_aton(ip)
result.append({"ip": line.strip(), "status": "valid"})
except socket.error:
result.append({"ip": line.strip(), "status": "invalid"})
print(json.dumps(result))

Finally, I got a fix:
import os
import sys
import json
from IPy import IP
filepath="E:/Work/"
filename="data.txt"
result = list()
with open(os.path.join(filepath+filename)) as file:
for line in file:
ip = line.strip()
if ip.startswith("0"):
result.append({"ip": line.strip(), "status": "invalid"})
else:
try:
ip_add=IP(ip)
result.append({"ip": line.strip(), "status": "Valid"})
except ValueError:
result.append({"ip": line.strip(), "status": "invalid"})
print(json.dumps(result))

python - extract a specific key / value from json file by a variable

a bit new to python and json.
i have this json file:
{ "hosts": {
"example1.lab.com" : ["mysql", "apache"],
"example2.lab.com" : ["sqlite", "nmap"],
"example3.lab.com" : ["vim", "bind9"]
}
}
what i want to do is use the hostname variable and extract the values of each hostname.
its a bit hard to explain but im using saltstack, which already iterates over hosts and i want it to be able to extract each host's values from the json file using the hostname variable.
hope im understood.
thanks
o.

You could do something along these lines:
import json
j='''{ "hosts": {
"example1.lab.com" : ["mysql", "apache"],
"example2.lab.com" : ["sqlite", "nmap"],
"example3.lab.com" : ["vim", "bind9"]
}
}'''
specific_key='example2'
found=False
for key,di in json.loads(j).iteritems(): # items on Py 3k
for k,v in di.items():
if k.startswith(specific_key):
found=True
print k,v
break
if found:
break
Or, you could do:
def pairs(args):
for arg in args:
if arg[0].startswith(specific_key):
k,v=arg
print k,v
json.loads(j,object_pairs_hook=pairs)
Either case, prints:
example2.lab.com [u'sqlite', u'nmap']

If you have the JSON in a string then just use Python's json.loads() function to load JSON parse the JSON and load its contents into your namespace by binding it to some local name
Example:
#!/bin/env python
import json
some_json = '''{ "hosts": {
"example1.lab.com" : ["mysql", "apache"],
"example2.lab.com" : ["sqlite", "nmap"],
"example3.lab.com" : ["vim", "bind9"]
}
}'''
some_stuff = json.loads(some_json)
print some_stuff['hosts'].keys()
---> [u'example1.lab.com', u'example3.lab.com', u'example2.lab.com']
As shown you then access the contents of some_stuff just as you would any other Python dictionary ... all the top level variable declaration/assignments which were serialized (encoded) in the JSON will be keys in that dictionary.
If the JSON contents are in a file you can open it like any other file in Python and pass the file object's name to the json.load() function:
#!/bin/python
import json
with open("some_file.json") as f:
some_stuff = json.load(f)
print ' '.join(some_stuff.keys())

If the above json file is stored as 'samplefile.json', you can write following in python:
import json
f = open('samplefile.json')
data = json.load(f)
value1 = data['hosts']['example1.lab.com']
value2 = data['hosts']['example2.lab.com']
value3 = data['hosts']['example3.lab.com']