Second question

[zfigov]

How can I know that I am creating another instance of the class? ( static variable in C++)

[ynonp]

C++ static variables == Python class variables:
https://www.tocode.co.il/bundles/python-verint/lessons/class-syntax?tab=article

(called משתני מחלקה in the article)

[zfigov]

I read the text but still didn't get it. Is a new instance created every
time you call the object- MyCounter()? Seems that it isn't if so what does
it mean when you just call the object without parameters?

Thanks
Zvi

On Wed, Jul 20, 2016 at 8:59 PM, ynonp notifications@github.com wrote:

C++ static variables == Python class variables:

https://www.tocode.co.il/bundles/python-verint/lessons/class-syntax?tab=article

—
You are receiving this because you authored the thread.
Reply to this email directly, view it on GitHub
#182 (comment),
or mute the thread
https://github.com/notifications/unsubscribe-auth/ATWpyHFOT4ifzCGzG3zugx4xn6laCkDqks5qXmH5gaJpZM4JQ2vz
.

[ynonp]

Every time you call a constructor function (i.e. MyCounter in your example) a new object is created. For example the following code prints "Hello" 3 times:

class HelloWorld(object):
    def __init__(self):
        print "Hello World"

a = HelloWorld()
b = HelloWorld()
c = HelloWorld()

Python calls __init__ magic method automatically each time a new instance is created and its job is to initialize data relevant to that instance (or other required system data).

In the counter example you can use __init__ to increase a counter stored as a class variable, thus keeping track of newly created objects

[zfigov]

But how do I know to initialize the first time? Is there some kind of
indication that this is the first time the object is initialized?

On Thu, Jul 21, 2016 at 8:21 AM, ynonp notifications@github.com wrote:

Every time you call a constructor function (i.e. MyCounter in your
example) a new object is created. For example the following code prints
"Hello" 3 times:

class HelloWorld(object):
def init(self):
print "Hello World"

a = HelloWorld()
b = HelloWorld()
c = HelloWorld()

Python calls init magic method automatically each time a new instance
is created and its job is to initialize data relevant to that instance (or
other required system data).

In the counter example you can use init to increase a counter stored
as a class variable, thus keeping track of newly created objects

—
You are receiving this because you authored the thread.
Reply to this email directly, view it on GitHub
#182 (comment),
or mute the thread
https://github.com/notifications/unsubscribe-auth/ATWpyDXpCaqD9FeLruv8O8YRjxdUuFaBks5qXwHYgaJpZM4JQ2vz
.

[ynonp]

That's what class variables are for. Here's a slightly modified version. This works because the variable s_text is initialised once before creating any objects

class HelloWorld(object):
    s_text = "Hello World"

    def __init__(self):
        print HelloWorld.s_text

a = HelloWorld()
b = HelloWorld()
c = HelloWorld()

[zfigov]

Ok, now I got it (I sent you solution).

class MyCounter(object):
count = 0 # this is only called once for all objects created
def init(self):
MyCounter.count += 1 # this uses the class property that is used in
all the objects created
In c1 = MyCounter() the c1 isn't used (we don't need to return a value)

Thanks

On Thu, Jul 21, 2016 at 8:34 AM, ynonp notifications@github.com wrote:

That's what class variables are for. Here's a slightly modified version.
This works because the variable s_text is initialised once before
creating any objects

class HelloWorld(object):
s_text = "Hello World"

def __init__(self):
    print HelloWorld.s_text

a = HelloWorld()
b = HelloWorld()
c = HelloWorld()

—
You are receiving this because you authored the thread.
Reply to this email directly, view it on GitHub
#182 (comment),
or mute the thread
https://github.com/notifications/unsubscribe-auth/ATWpyHkR0ue6LwLLotAhZ1-7pfYMhFPoks5qXwTZgaJpZM4JQ2vz
.