More on list comp and generators - Intermediate Python Programming p.5

Welcome to part 5 of the intermediate Python programming tutorial series. In this part, we're going to talk more about list comprehension and generators.

[smebird]

One of the beautiful things about the internet, is that a great course like this is available years after it was published on YouTube. Thank you so much, I'm having a lot of fun!

[maxlee]

The most awesome part of this video happened in the last 30 seconds. Other people, don't make the mistake of skipping ahead to the next videos.

[ConorFenlon]

I'm sitting here, drinking a glass of red wine, waiting patiently for the full release of the nnfs book, brushing up on my coding, and I'm very happy about it.

[iVandal]

i think this is one of the most elegant parts of Python. Syntax is so clean!

[krishnasrujan]

n=int(input("enter a number "))

[print(i) for i in (item for item in range(n) if item % 2==0)]
printing values of generator series in single line

[mohisolanki]

Quick tip if you want build a list or tuple out of generator
x = (i for i in range(20)) # A generator
y = [*x] # unpack generator or y = (*x, ) # to build a tuple

[MultiSokom]

15:05 - This also works! :

for i in (print(i) for i in range(5)):
pass

[esclavosoy]

This intermediate Python course is awesome, it's exactly what I've been looking for. Thanks!

[_adaldo]

At 15:05, you don't need to state 'i' in the for loop, right? You may as well

for i in xyz:
pass

And you still get the prints, since the five prints are called upon iteration.

On a somehow related note,

xyz = [print(i) for i in range(3)]
#1
#2
#2

print(xyz)
# [None, None, None]

for i in xyz:
print(i)
# None
# None
# None

right?

And youtube needs markdown.

[rotrose]

Thank you, this is the very series I am looking for

[gautamkumargupta]

(print(i) for i in x)
In the above case what will be stored in memory. I am getting the following output if I am trying to execute the following set of instructions

Program::
input_list = [2, 4, 6, 8, 9, 23, 45, 78, 90, 6576, 75, 8797, 980]

def div_by_two(num):
if num % 2 == 0:
return True
else:
return False

x = [i for i in input_list if div_by_two(i)]
z = (print(i) for i in x)
for i in z:
print (i)

## Output comes this. What is the meaning of None here?
2
None
4
None
6
None
8
None
78
None
90
None
6576
None
980
None

[theJUSTICEof]

Although this tutorial does what it was intended for, I feel like map and filter should've been mentioned from the start.

I really like the intermediate Python tutorials,
keep up the good work!

[andreisima]

SELECT column FROM table WHERE condition 1 <logic operation> condition 2. Quite similar. In python 3 I will try if works the second condition. Interesting. That is just a query not a hole comparison computation.

[serhiy]

you can shorten the body of div_by_five() to return num % 5 == 0

[Nemonamir]

u can just use

def div_by_5(num):
return num%5==0

[eunsolhong]

the generator "xyz = (print(i) for i in range(5))", and "for i in xyz: i"...

I got the same result using "for i in xyz: pass" instead of "for i in xyz: i", and I did "for i in xyz: print(i)" then it shows "0; none; 1; none; 2; none and so on".

Maybe each "i" did not meaning print(i) but the return value of print(i), I think.

[tkdevlop]

i don't understand first time i do myself and see the video again and again until i understand completely #this is just my opinion for learning

[abhi-musicma]

The last was mind blowing where you just used i instead of print(i) cause "i" it self was an object of print() that was like so logical and mind blowing just loving your videos a great explanation Thank you so much.

I would so much like to add you as a friend on fb please let me know if I can add you ^_^

[finfan]

I started out understanding, got confused as you stumbled, and then understood again once you understood what you were trying to say. This was a longer but better explanation than the one I looked at earlier today. Do you put a lot of planning into what you are going to say?
The nesting is a bit mad though. Seems like it could be more human readable, which I thought was the point of python, if it were a different syntax. If I ever get deep enough in this I might write a generator creation function.

[NitinChauhan-vhyk]

Running the code (xyz = (i for i in input_list if div_by_five(i)) and then printing the elements of xyz also prints a list of None at the end on idle. Any idea why?