I am writing a code that has a class Fraction with attributes Numerator and Denominator. The Output should display the fraction in a simplified form. For e.g. 20/100 should be display as 1/5.
I have tried the below code but getting a Type Error as below:
TypeError: unsupported operand type(s) for /: 'int' and 'NoneType'
class fraction:
def get_data(self):
self.__num=int(input("Enter the Nr:"))
self.__deno=int(input("Enter the Dr:"))
if (self.__deno==0):
print("Fraction not possible")
exit()
def display_data(self):
self.__simplify()
print(self.__num,"/",self.__deno)
def __simplify(self):
print("The simplified fraction is")
common_divisor=self.__GCD(self.__num,self.__deno)
self.__num=(self.__num)/(common_divisor)
self.__deno=(self.__deno)/(common_divisor)
def __GCD(self,a,b):
if (b==0):
return a
else:
self.__GCD(b,a%b)
f=fraction()
f.get_data()
f.display_data()
I have no clue how to solve this Error. Please help me as i am new to Python and want to build strong basics.
The problem is in this function definition:
def __GCD(self,a,b):
if (b==0):
return a
else:
self.__GCD(b,a%b)
There's no return statement on the else clause. (Also, the else clause can be implicit instead of explicit.) Instead try:
def __GCD(self, a, b):
if b == 0:
return a
return self.__GCD(b, a % b)
Related
Can someone please tell me why the error happens and possible alternatives in solving this
My code:
def actual = " [{"inputs":[{"__typename":"ElementalField"}],"constraint":"FILE-STATUS:REPORT-STATUS:REPORT-STATUS-1='0'","source":{"sourceCodeFiles":[{"fileName":"/usr/src/workspace/PC/source/cobol/PCCTRE.cob","sourceLines":[{"nodes":[{"id":"8326"}],"lineNumber":620}]}],"__typename":"Source"},"branchExecuted":false},{"inputs":[{"__typename":"ElementalField"}],"constraint":"FILE-STATUS:TRAND-STATUS:TRAND-STATUS-1='0'","source":{"sourceCodeFiles":[{"fileName":"/usr/src/workspace/PC/source/cobol/PCCTRE.cob","sourceLines":[{"nodes":[{"id":"8369"}],"lineNumber":634}]}],"__typename":"Source"},"branchExecuted":false}]"
def expected = "[{"inputs":[{"__typename":"ElementalField"}],"constraint":"FILE-STATUS:REPORT-STATUS:REPORT-STATUS-1='0'","source":{"sourceCodeFiles":[{"fileName":"/usr/src/workspace/PC/source/cobol/PCCTRE.cob","sourceLines":[{"nodes":[{"id":"8326"}],"lineNumber":620}]}],"__typename":"Source"},"branchExecuted":false},{"inputs":[{"__typename":"ElementalField"}],"constraint":"FILE-STATUS:TRAND-STATUS:TRAND-STATUS-1='0'","source":{"sourceCodeFiles":[{"fileName":"/usr/src/workspace/PC/source/cobol/PCCTRE.cob","sourceLines":[{"nodes":[{"id":"8366"}],"lineNumber":634}]}],"__typename":"Source"},"branchExecuted":false}]"
def removedA = actual.replaceAll("[_]","").trim();
def removedE = expected.replaceAll("[_]","").trim();
def json = new groovy.json.JsonSlurper().parseText(removedA)
//Checks all elements of resource one by one and compare with expectedData
json.each{k, v -> assert v == removedE."$k" }
Here is the error:
groovy.lang.MissingMethodException: No signature of method: Script23$_run_closure1.doCall() is applicable for argument types: (org.apache.groovy.json.internal.LazyMap) values: [[inputs:[[typename:ElementalField]], constraint:FILE-STATUS:REPORT-STATUS:REPORT-STATUS-1='0', ...]] Possible solutions: doCall(java.lang.Object, java.lang.Object), findAll(), findAll(), isCase(java.lang.Object), isCase(java.lang.Object) error at line: 37
I have written a code using if, try/except clause. I want to use "try" to check whether the parameters are correct and if those are correct the "print" function will run.
If the parameters are not right then the error message will be printed and the print section will not run.
The problem is when I am correct input it is running but when I am giving wrong input, after printing the error message I am getting NameError, saying "room1" is not defined. I understood why it is happening but I am confused how to get the correct output without getting an error.
My code is:
class Hotel:
def __init__(self,room,catagory):
if type(room) != int:
raise TypeError()
if type(catagory) != str:
raise TypeError()
self.room = room
self.catagory = catagory
self.catagories = {"A":"Elite","B":"Economy","C":"Regular"}
self.rooms = ["0","1","2","3","4","5"]
def getRoom(self):
return self.room
def getCatagory(self):
return self.catagories.get(self.catagory)
def __str__(self):
return "%s and %s"%(self.rooms[self.room],self.catagories.get(self.catagory))
try:
room1 = Hotel(a,"A")
except:
print("there's an error")
print (room1)
Your print should be in the try segment of your code as it will always execute whether there is an error or not.
class Hotel:
def __init__(self,room,catagory):
if type(room) != int:
raise TypeError()
if type(catagory) != str:
raise TypeError()
self.room = room
self.catagory = catagory
self.catagories = {"A":"Elite","B":"Economy","C":"Regular"}
self.rooms = ["0","1","2","3","4","5"]
def getRoom(self):
return self.room
def getCatagory(self):
return self.catagories.get(self.catagory)
def __str__(self):
return "%s and %s"%(self.rooms[self.room],self.catagories.get(self.catagory))
Initialization
try:
room1 = Hotel(a,"A")
print (room1)
except:
print("there's an error")
I am working with eXistDB in python and leveraging the eulxml library to handle mapping from the xml in the database into custom objects. I want to then serialize these objects to json (for another application to consume) but I'm running into issues. jsonpickle doesn't work (it ends up returning all sorts of excess garbage and the value are the fields aren't actually encoded but rather their eulxml type) and the standard json.dumps() is simply giving me empty json (this was after trying to implement the solution detailed here). The problem seems to stem from the fact that the __dict__ values are not initialised __oninit__ (as they are mapped as class properties) so the __dict__ appears empty upon serialization. Here is some sample code:
Serializable Class Object
class Serializable(dict):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# hack to fix _json.so make_encoder serialize properly
self.__setitem__('dummy', 1)
def _myattrs(self):
return [
(x, self._repr(getattr(self, x)))
for x in self.__dir__()
if x not in Serializable().__dir__()
]
def _repr(self, value):
if isinstance(value, (str, int, float, list, tuple, dict)):
return value
else:
return repr(value)
def __repr__(self):
return '<%s.%s object at %s>' % (
self.__class__.__module__,
self.__class__.__name__,
hex(id(self))
)
def keys(self):
return iter([x[0] for x in self._myattrs()])
def values(self):
return iter([x[1] for x in self._myattrs()])
def items(self):
return iter(self._myattrs())
Base Class
from eulxml import xmlmap
import inspect
import lxml
import json as JSON
from models.serializable import Serializable
class AlcalaBase(xmlmap.XmlObject,Serializable):
def toJSON(self):
return JSON.dumps(self, indent=4)
def to_json(self, skipBegin=False):
json = list()
if not skipBegin:
json.append('{')
json.append(str.format('"{0}": {{', self.ROOT_NAME))
for attr, value in inspect.getmembers(self):
if (attr.find("_") == -1
and attr.find("serialize") == -1
and attr.find("context") == -1
and attr.find("node") == -1
and attr.find("schema") == -1):
if type(value) is xmlmap.fields.NodeList:
if len(value) > 0:
json.append(str.format('"{0}": [', attr))
for v in value:
json.append(v.to_json())
json.append(",")
json = json[:-1]
json.append("]")
else:
json.append(str.format('"{0}": null', attr))
elif (type(value) is xmlmap.fields.StringField
or type(value) is str
or type(value) is lxml.etree._ElementUnicodeResult):
value = JSON.dumps(value)
json.append(str.format('"{0}": {1}', attr, value))
elif (type(value) is xmlmap.fields.IntegerField
or type(value) is int
or type(value) is float):
json.append(str.format('"{0}": {1}', attr, value))
elif value is None:
json.append(str.format('"{0}": null', attr))
elif type(value) is list:
if len(value) > 0:
json.append(str.format('"{0}": [', attr))
for x in value:
json.append(x)
json.append(",")
json = json[:-1]
json.append("]")
else:
json.append(str.format('"{0}": null', attr))
else:
json.append(value.to_json(skipBegin=True))
json.append(",")
json = json[:-1]
if not skipBegin:
json.append('}')
json.append('}')
return ''.join(json)
Sample Class that implements Base
from eulxml import xmlmap
from models.alcalaMonth import AlcalaMonth
from models.alcalaBase import AlcalaBase
class AlcalaPage(AlcalaBase):
ROOT_NAME = "page"
id = xmlmap.StringField('pageID')
year = xmlmap.IntegerField('content/#yearID')
months = xmlmap.NodeListField('content/month', AlcalaMonth)
The toJSON() method on the base is the method that is using the Serializable class and is returning empty json, e.g. "{}". The to_json() is my attempt to for a json-like implementation but that has it's own problems (for some reason it skips certain properties / child objects for no reason I can see but thats a thread for another day).
If I attempt to access myobj.keys or myobj.values (both of which are exposed via Serializable) I can see property names and values as I would expect but I have no idea why json.dumps() produces an empty json string.
Does anyone have any idea why I cannot get these objects to serialize to json?! I've been pulling my hair out for weeks with this. Any help would be greatly appreciated.
So after a lot of playing around, I was finally able to fix this with jsonpickle and it took only 3 lines of code:
def toJson(self):
jsonpickle.set_preferred_backend('simplejson')
return jsonpickle.encode(self, unpicklable=False)
I used simplejson to eliminate some of the additional object notation that was being added and the unpicklable property removed the rest (I'm not sure if this would work with the default json backend as I didn't test it).
Now when I call toJson() on any object that inherits from this base class, I get very nice json and it works brilliantly.
def usersdecision(n):
if option == n:
calculation.format(n)()
Is there a way to get calculation to become calculation + the value of n then (),
so if n=1 calculation would become calculation1().
Here is an inelegant way of doing it. Pass in a list, see how long it is and use the length to call different routines
import sys
def userd(*n):
if (len(n) == 1):
return calc1(n[0])
if (len(n) == 2):
return calc2(n[0],n[1])
if (len(n) > 2):
warn("bad input",n)
sys.exit(1)
def calc1(x):
return x*2
def calc2(x,x2):
return x**x2
assert userd(1) == 2
assert userd(2,3) == 8
print "it works"
I would like to write a bit of code that calls a function specified by a given argument. EG:
def caller(func):
return func()
However what I would also like to do is specify optional arguments to the 'caller' function so that 'caller' calls 'func' with the arguments specified (if any).
def caller(func, args):
# calls func with the arguments specified in args
Is there a simple, pythonic way to do this?
You can do this by using arbitrary argument lists and unpacking argument lists.
>>> def caller(func, *args, **kwargs):
... return func(*args, **kwargs)
...
>>> def hello(a, b, c):
... print a, b, c
...
>>> caller(hello, 1, b=5, c=7)
1 5 7
Not sure why you feel the need to do it, though.
This already exists as the apply function, though it is considered obsolete due to the new *args and **kwargs syntax.
>>> def foo(a,b,c): print a,b,c
>>> apply(foo, (1,2,3))
1 2 3
>>> apply(foo, (1,2), {'c':3}) # also accepts keyword args
However, the * and ** syntax is generally a better solution. The above is equivalent to:
>>> foo(*(1,2), **{'c':3})