NameError question - def(self,master) - master not in namespacewithin class?

[harijay]

Hi I am new to writing module and object oriented python code. I am
trying to understand namespaces and classes in python.

I have the following test case given in three files runner , master
and child. I am getting an error within child where in one line it
understands variable master.name and in the next line it gives a
NameError as given here

" print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)
NameError: name 'master' is not defined"


Sorry for a long post because I dont know how to frame my question.
I am pasting the code contained in the three files and the error
message here
Thanks for your help
harijay


The detailed error I get is
hazel:tmp hari$ python runner.py
Traceback (most recent call last):
File "runner.py", line 3, in <module>
import child
File "/Users/hari/rpc-ccp4/tmp/child.py", line 1, in <module>
class child():
File "/Users/hari/rpc-ccp4/tmp/child.py", line 9, in child
print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)
NameError: name 'master' is not defined

#File runner.py
#!/usr/bin/python
import master
import child

if __name__=="__main__":
print "RUNNING RUNNER"
m = master.master("hj","oldhj")
s = child.child(m)
print "Now I have the variable master name %s and master.trash %s" %
(m.name , m.trash)

#File master.py
class master():
name=""
trash=""

def __init__(self,name,trash):
self.name = name
self.trash = trash


#File child.py
class child():
def __init__(self,master):
print "Master name is %s" % master.name
print "Now seeting master name to setnameinchild in child.py "
tmp = master.trash
master.trash = master.name
master.name = "setnameinchild"
print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)

 

[bieffe62]

Hi I am new to writing module and object oriented python code. I am
trying to understand namespaces and classes in python.

I have the following test case given in three files runner , master
and child. I am getting an error within child where in one line it
understands variable master.name and in the next line it gives a
NameError as given here

"    print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)
NameError: name 'master' is not defined"

Sorry for a long post because I dont know how to  frame my question.
I am pasting the code contained in the three files and the error
message here
Thanks for your help
harijay

The detailed error I get is
hazel:tmp hari$ python runner.py
Traceback (most recent call last):
  File "runner.py", line 3, in <module>
    import child
  File "/Users/hari/rpc-ccp4/tmp/child.py", line 1, in <module>
    class child():
  File "/Users/hari/rpc-ccp4/tmp/child.py", line 9, in child
    print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)
NameError: name 'master' is not defined

#File runner.py
#!/usr/bin/python
import master
import child

if __name__=="__main__":
        print "RUNNING RUNNER"
        m = master.master("hj","oldhj")
        s = child.child(m)
        print "Now I have the variable master name %s and master.trash %s" %
(m.name , m.trash)

#File master.py
class master():
        name=""
        trash=""

        def __init__(self,name,trash):
                self.name = name
                self.trash = trash

#File child.py
class child():
        def __init__(self,master):
                print "Master  name is %s" % master.name
                print  "Now seeting master name to setnameinchild in child.py "
                tmp = master.trash
                master.trash = master.name
                master.name = "setnameinchild"
        print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)

You need to have an import master in child.py too.

Ciao

 

[Jerry Hill]

Hi I am new to writing module and object oriented python code. I am
trying to understand namespaces and classes in python.

I have the following test case given in three files runner , master
and child. I am getting an error within child where in one line it
understands variable master.name and in the next line it gives a
NameError as given here

#File child.py
class child():
def __init__(self,master):
print "Master name is %s" % master.name
print "Now seeting master name to setnameinchild in child.py "
tmp = master.trash
master.trash = master.name
master.name = "setnameinchild"
print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)

The last line (starting with print), is not indented to the correct
level. Assuming it's supposed to be part of the child class's
__init__ method, it needs to line up with the rest of that method.

 

[harijay]

Thanks beiff for your prompt reply - But I shouldnt need to import
master in child.

Actually and very strangely. The problem fixed itself without any
change to my code.
I dont understand how. It may have been a problem with a bad *.pyc
lingering around . But now I cannot get the old NameError to repeat
itself..its very weird
Here is the new code and it runs just fine ..I am absolutely confused
as to why it failed several times in a row and then fixed itself.


Here is the new code just to convince myself that there is absolutely
no change;


#File runner.py
#!/usr/bin/python
import master
import child

if __name__=="__main__":
print "RUNNING RUNNER"
m = master.master("hj","oldhj")
s = child.child(m)
print "Now I have the variable master name %s and master.trash %s" %
(m.name , m.trash)


#File child.py
class child():

def __init__(self,master):
print "Master name is %s" % master.name
print "Now seeting master name to setnameinchild in child.py "
tmp = master.trash
master.trash = master.name
master.name = "setnameinchild"
print "Reset name now from %s to %s , oldname %s is saved in
mastertrash" % (master.trash, master.name , master.trash)

#File master.py
class master():
name=""
trash=""

def __init__(self,name,trash):
self.name = name
self.trash = trash

Produces the output:
hazel:tmp hari$ python runner.py
RUNNING RUNNER
Master name is hj
Now seeting master name to setnameinchild in child.py
Reset name now from hj to setnameinchild , oldname hj is saved in
mastertrash
Now I have the variable master name setnameinchild and master.trash hj

 

[harijay]

Thanks Jerry and beiff ,
Jerry was right, it was an indent problem . Between using my text
editor and running from commandline something went out of sync and I
didnt catch it probably.
I can now reproduce the error with a bad ident .

These are my first posts to comp.lang.python..and I am very grateful
to everyone for their time .

harijay

 

[Bruno Desthuilliers]

(e-mail address removed) a écrit :
<OT>
bieffe, please, learn to snip irrelevant material...

(snip)
(snip)

You need to have an import master in child.py too.

Nope. The 'child' class is passed a 'master' instance when instanciated.
You got confused by the bad naming.

<OP>
The convention in Python is to name classes in CamelCase. Your classes
should be named 'Master' and 'Child'.
</OP>