python get new random name for every call of class [duplicate]

Question

I am trying to get new random name every time I call class. I am defining it as

def namemethod(): return ''.join(random.choice(string.lowercase) for x in range(5)) class Test(object): def __init__(self, name=namemethod()): self.name = name

And I am calling Test class via for loop to get new name but I keep getting same name, isn't it suppose to call init method and get new random name?

for i in range(5): person = Test() print person.name

Why person = Test() not calling namemethod everytime?

@SilverSlash, probably docs.python.org/2/library/string.html#string.lowercase — chickity china chinese chicken
– chickity china chinese chicken, Commented Jan 29, 2018 at 17:55
Answers below are correct. FYI, a more detailed explanation: "Common Gotchas - Mutable Default Arguments". — CodeBoy
– CodeBoy, Commented Jan 29, 2018 at 18:10

Dennis Soemers · Accepted Answer · 2018-01-29 17:53:39Z

In this code:

class Test(object): def __init__(self, name=namemethod()): self.name = name

The default argument

name=namemethod()

only gets evaluated a single time for the entire class (default arguments always only get evaluated once)

What you probably want to do instead, is use name=None as default value for the name argument. The, in __init__(), you could do something like this:

class Test(object): def __init__(self, name=None): if name is None: name = namemethod() self.name = name

Ayush · Accepted Answer · 2018-01-29 17:54:58Z

in your code, the name=namemethod() default argument is replaced permanently by a single instance returned by a call to namemethod

Your desired behaviour can be achieved using:

def namemethod(): return ''.join(random.choice(string.lowercase) for x in range(5)) class Test(object): def __init__(self, name=None): self.name = name if name is not None else namemethod()

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