How to declare a LIST as GLOBAL in python

[getmanup]

Can we declare using th keyword "global" in declaring a global array?

ie like global arr = []

This throws an error saying invalid syntax.

[dwblas]

Not enough info. What is the code and what is the error message. Finally, you should not be using globals. Pass the list (not array) to the function and return it, or better still, use a class. A link to a book describing function args in case you don't know http://www.greenteapress.com/thinkpy...l/book007.html

[getmanup]

I declared a list as I had to append some threads into it.

global th = []
th.append(thread)

These 2 lines of code were written in one function. In another function I want to join them like:

for t in th
     t.join()
 

But this code throws an error telling that global th= [] is invalid syntax.

[Glenton]

@getmanup
When you say threads do you mean this kind of thread? I'm pretty sure that joining them is not valid. So what @dwblas was saying was that you should rather pass your "th" variable across explicitly.

def firstcode():
     ...
    th=[]
    th.append(thread)
    ...
    return th
 
def nextmethod(th):
    for t in th:
        t.join()

But if you really want to make th global, just add

global th
th=[]

to your code.

[getmanup]

@Glenton
thank you so much... it worked

but u did say that joining threads like that is not a good idea...I am really in the beginner level...so could you explain why you said so..if its ok for u ...

[Glenton]

Um...I don't think you're using threads in the coding sense. Probably it's just a string, so don't worry about it. If you're not sure, then you're definitely not using them!