Calling a list of methods with next()-CodePudding

I'd like to call a set of methods in succession -- the same way we use next() to go through an iterable.

The problem is that if I put them in a iter() they are all implicitly called at the same time, and next() does not work as it should.

What am I missing?

Thank you very much!

CodePudding user response：

Is this what you want to achieve? I've edited the original answer to show that it also allows you to pass args to these functions.

def append_num(x):
    x.append(4)
    
def append_other_num(x):
    x.append(5)


func_l = ['append_num', 'append_other_num']

l = [1, 2, 3]
print(l)

for x in func_l:
    eval(x   '(l)')
    print(l)

# Output:
# [1, 2, 3]
# [1, 2, 3, 4]
# [1, 2, 3, 4, 5]

CodePudding user response：

Yes, as I thought, you are saving the results of calls into a list:

f = iter([print("A"), print("B")])

The list will contain two Nones that are the result of calling print() (and btw print("A") is called first and print("B") second, so not at the same time, but before f is created)

What you can do instead is:

funcs = iter([lambda:print("A"), lambda:print("B")])

f = next(funcs)
print('before call')
f()
print('after call')

Output:

before call
A
after call