When I declare a function inside a class I get name error-CodePudding

The first code work properly but when I declare the 'toStr' function(or method) inside the class I get error. What's wrong with this code? First Code:

class Test:
    def __init__(self,hour,minute,second):
        self.hour=hour
        self.minute=minute
        self.second=second

# Return String Time Format
def toStr(self):
    return str(self.hour) ":" str(self.minute) ":" str(self.second)
t=Test(10,20,50)
print(toStr(t))

The second code with NameError:

class Test:
    def __init__(self,hour,minute,second):
        self.hour=hour
        self.minute=minute
        self.second=second

# Return String Time Format
    def toStr(self):
        return str(self.hour) ":" str(self.minute) ":" str(self.second)
t=Test(10,20,50)
print(toStr(t))

CodePudding user response：

Here is my code,

class Test:
    def __init__(self,hour,minute,second):
        self.hour=hour
        self.minute=minute
        self.second=second

# Return String Time Format
    def toStr(self):
        return str(self.hour) ":" str(self.minute) ":" str(self.second)

t=Test(10,20,50)
print(t.toStr())

here is my output,

10:20:50

You can't call the toStr function outside the t object (Test class), you need to call it using the dot operator because the toStr function belongs to the Test class now.

CodePudding user response：

You need to either call the method on the object like:

print(t.toStr())

print(Test.toStr(t))

CodePudding user response：

-> As you are working with object-oriented concepts. you should be familiar with it. whenever you create a class you have to create object of it to use its functionality

class MyTest: #class
    def __init__(self, hour, minute, second): #constructor
        self.hour=hour
        self.minute=minute
        self.second=second

    def toStr(self): #method
        return str(self.hour) ":" str(self.minute) ":" str(self.second)

obj=MyTest(4,5,5) # class object
print(obj.toStr()) # to call toStr() method you have to use it with a object.