why the output is not logically right? - json

Question

i'm trying to implement this code. here are the problems:
1. i want to use variable typ_transport in further coding not just inside if.(it does not recognize the variable.)
2. the logic seems to be right but when i change the values in jsonStr (e.g. "walk" : true to "walk" : fasle ) the output does not print the right output.
Could any one help me with this? thanks
import json
jsonStr = '{"walk" : true, "bike" : false, "tram" : false}'
inputvar = json.loads(jsonStr)
if inputvar['walk'] == 'True' and inputvar['bike'] == 'False' :
typ_transport='foot'
elif inputvar['walk'] == 'False' and inputvar['bike'] == 'True' :
typ_transport='bicycle'
class transport:
if typ_transport=='foot':
velocity=80
typ='foot'
elif typ_transport=='bicycle':
velocity=330
typ='bicycle'
def __init__(self,typ,velocity):
self.velocity = velocity
self.typ = typ
if inputvar['tram'] == 'False' :
radius= T*transport.velocity
print (radius)
else :
print (typ_transport, 333)

Answer 1

I see some problems in the code, so I'll try to point them out as I go through your questions
i want to use variable typ_transport in further coding not just inside if.(it does not recognize the variable.)
The reason why you can't access the typ_transport variable is that it's created inside the if statement. If you wish to access the variable later in the code, you would have to change the scope of the typ_transport into a global scope.
You can do this in two ways. First is creating a global variable before you start the if statement
typ_transport = ""
if inputvar['walk'] == True and inputvar['bike'] == False:
typ_transport = 'foot'
The second way would be to create a global variable inside the if statement using global keyword. This way is highly discouraged since it is easy to lose the track of variables and their scopes.
the logic seems to be right but when i change the values in jsonStr (e.g. "walk" : true to "walk" : fasle ) the output does not print the right output
Aside from the spelling errors you got there, Python booleans are kept in True, and False (no single quote, first letter capitalized). When you use JSON module, it should parse correctly, but it's always good idea to double check.
Lastly, You are using class but it's not organized. Let's try to make it look little more tidier.
class transport:
def __init__(self,typ_transport): #utilizing global variable we created
if typ_transport == 'foot':
velocity = 80
self.typ_transport = self.typ_transport
self.velocity = velocity
elif typ_transport == 'bicycle':
......
Now to get the velocity when typ_transport = 'foot'
passenger = transport(typ_transport) #creating passenger object
velocity = passenger.velocity

Answer 2

import json
jsonStr = ('[{"walk" : true, "bike" : false, "tram" : false}, '
'{"walk" : false, "bike" : true, "tram" : false}, '
'{"walk" : false, "bike" : false, "tram" : true},'
'{"walk" : false, "bike" : false, "tram" : false}]'
)
inputvar = json.loads(jsonStr)
class Transport:
def __init__(self,typ):
self.typ = typ
self.velocity = None
if typ == 'foot':
self.velocity = 80
elif typ == 'bicycle':
self.velocity = 330
elif typ == 'tram':
self.velocity = 333
for var in inputvar:
typ_transport = None
if var['walk'] is True and var['bike'] is False:
typ_transport = 'foot'
elif var['walk'] is False and var['bike'] is True:
typ_transport = 'bicycle'
elif var['tram'] is True:
typ_transport = 'tram'
transport = Transport(typ_transport)
print(transport.typ, transport.velocity)
This make more sense to me.
Feel free to change it, if I misunderstood your logic.