Technical Thursday – JSON outputs in Python
Outputs, output formatting…this is a quite interesting topic during your development activities. Every time when you create a function you want to provide reusable code with excellent outputs…but how can you achieve this?
Maybe you feel this is a simple question and the answer is also simple. Nevertheless you realize some weeks later this is a little bit complex area. I mean when you choose a result type or solution you have some direction you can choose.
- True/False
- Simple string
- Nothing 🙁
- Result code (0, 1, …)
- JSON
My personal choice is JSON because easy to manage and you can provide several important information for re-usage via that . For example in Azure-Cli every time you receive JSON object which contains the most important information for current activity. Moreover a JSON object is easily managed by Python.
And now I show some useful example for JSON output management by Python.
0. Use JSON in python
JSON management is very simple in Python. You merely need to import JSON module.
# Import JSON module
import json
# Define JSON format string
mystring = '{"name": "Python", "version": "2.7"}'
# Convert string to JSON
myjson = json.loads(mystring)
# Use JSON data
print "{0}".format(myjson["name"])
1. Return from string
When you have a string in JSON format in your function and you would like to use it as a JSON object you need to convert the string to JSON.
# Define JSON format string
mystring = '{"name": "Python", "version": "2.7"}'
# my Function
def myFunction(inputString):
# Import JSON module
import json
# Try to convert to JSON
try:
# Convert string to JSON
myjson = json.loads(inputString)
# Return with result
return myjson["name"]
except:
# Error handling
return False
# Call function
myFunction(mystring)
To convert string to JSON object you can use the “json.loads()” method.
2. Return from JSON
Sometimes you have a JSON object and you would like to give back it via your function in string format.
# Define JSON format string
mystring = '{"name": "Python", "version": "2.7"}'
# my Function
def myFunction(inputString):
# Import JSON module
import json
# Try to convert to JSON
try:
# Convert string to JSON
myjson = json.loads(inputString)
# Return with result
return json.dumps(myjson)
except:
# Error handling
return False
# Call function
myFunction(mystring)
To convert JSON object to string you can use the “json.dumps()” method.
3. Return custom string
Finally you can create string output which is built by you.
# my Function
def myFunction(inputString):
# Return with result
return '{"status": "success", "message": "%s"}' % (inputString)
# Call function
myFunction("This is a string")
Here you should not import json module to create JSON format output
Of course can combine them and use other formats…Let’s try them…
