I am new to python. I have a few questions coming from an armature!

[Steven D'Aprano]

On Wednesday 17 August 2016 04:46, alister wrote:

> > squared_plus_one_list = map(lambda x: x**2 + 1, some_list)
> 
> probably the cleanest example I have seen so far, & I still cant see the
> point

Hmmm. Well, let's have a look at some analogies with other kinds of values.

Out of each pair of examples, *in general* would you prefer (A) or (B)?

I realise that there are occasions where we might deliberate choose to assign 
an intermediate value to its own variable, but all else being equal, which 
would you prefer?


#A
alist = []
alist.append(2)
alist.append(4)
alist.append(8)
process(alist)


#B
process([2, 4, 8])



#A
value = 0
for i in range(100):
    value += 1
process(value)

#B
process(100)



#A
tmp = get_some_string()
s = tmp[1]
s += tmp[2]
s += tmp[3]
process(s)

#B
process(get_some_string()[1:4])



#A
def callback(btn):
    return btn.do_the_thing(42) or default
the_button.setcommand(callback)
process(the_button)

#B
the_button.setcommand(lambda btn: btn.do_the_thing(42) or default)
process(the_button)



If you find yourself preferring B, B, B, A, you might ask yourself what makes a 
function different that you prefer to keep temporary functions around where 
they're not needed.




-- 
Steve