Don't forget lambdas! We don't always need to define a function if we're checking something more simple. We can also return the result of the IF check rather than writing out a full IF/ELSE clause: `return x < 1600 and y >= 2` will return True or False itself.
I know it's a video just about the filter function, but you could add a "list comprehension" for this example in this video to show a more professional and cooler alternative to the filter function. Then it will be easier to understand the logic of one and the other method, simple 2 in 1. 1 line of code vs 9 😁 x = [key for (key, value) in avail_units.items() if value["price"] < 1600 and value["bedrooms"] >= 2]
There are two quite important uses with the filter function that you didnt mention: 1. You can use a lambda inside the function: "filter(lambda x: x % 2 == 0, range(10))" 2. You can use None as a special function to create a type safe non-null collection invariant. Say you have a list (values) of None or integers (list[None | int]) and you only want the list of integers you can use "filter(None, values)" to get a "Iterable[int]" type. which only contains the integers from the list. Additionally you can also create filters that are easier to read using the comprehension syntax: values = (num for num in numbers if num % 2 == 0)
Returning True from an if and False from an else is the same as returning the condition. I prefer the second way because it's simpler. ¿Which do you choose and why?
@@foralxold comment, but the expression next to the if statement is itself a Boolean value. So the expression “small_units[unit_num][‘price’] < 1600 and avail_units[unit_num][‘bedrooms’] >= 2” will reduce down to either “True” or “False”. Thus, you can simply return the expression itself, rather than using it for the if statement to return “True” or “False”.
Hey, thanks! No advantage, list comprehension can be used interchangeably with the filter and map functions. I actually prefer list comprehension in most cases.
sometimes you learn something because you tried to name something the wrong thing (in hindsight, my list should have been called "mask" instead of "filter") and have to google it when the IDE changes your text color.
def filter(predicate, iterable): for item in iterable: if predicate(item): yield item Or, if you prefer a one-liner: filter = lambda p, it: (item for item in it if p(item)) That's all it does. And now you know why only dict keys are used without their values: for loops use dict keys unless you use the dict.items() method.
Don't forget lambdas! We don't always need to define a function if we're checking something more simple.
We can also return the result of the IF check rather than writing out a full IF/ELSE clause: `return x < 1600 and y >= 2` will return True or False itself.
Does that mean lambda x: return x < 1600 and y >=2 would work in place of the filter function in this case?
@@AlbrechtProud1 It'd be more like `lambda i: return obj[i][x] < 1600 and obj[i][y] >= 2`, but essentially yes.
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I know it's a video just about the filter function, but you could add a "list comprehension" for this example in this video to show a more professional and cooler alternative to the filter function. Then it will be easier to understand the logic of one and the other method, simple 2 in 1. 1 line of code vs 9 😁
x = [key for (key, value) in avail_units.items() if value["price"] < 1600 and value["bedrooms"] >= 2]
There are two quite important uses with the filter function that you didnt mention:
1. You can use a lambda inside the function: "filter(lambda x: x % 2 == 0, range(10))"
2. You can use None as a special function to create a type safe non-null collection invariant. Say you have a list (values) of None or integers (list[None | int]) and you only want the list of integers you can use "filter(None, values)" to get a "Iterable[int]" type. which only contains the integers from the list.
Additionally you can also create filters that are easier to read using the comprehension syntax:
values = (num for num in numbers if num % 2 == 0)
Is the None case explicitly mentioned in the source code, or is it a side-effect of how the function was implemented?
Cool videos! How do you get such a clean terminal in vs code?
I need to know too!
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1:55 Why not just return the bool directly?
Readability !!
Such a wonderful video! Just what I needed to start using the filter function, with proper if…else clauses!!!
Returning True from an if and False from an else is the same as returning the condition. I prefer the second way because it's simpler. ¿Which do you choose and why?
what do you mean by it is the same as returning the condition ? example ?
@@foralxold comment, but the expression next to the if statement is itself a Boolean value. So the expression “small_units[unit_num][‘price’] < 1600 and avail_units[unit_num][‘bedrooms’] >= 2” will reduce down to either “True” or “False”. Thus, you can simply return the expression itself, rather than using it for the if statement to return “True” or “False”.
Hey b001, love the videos! Is there an advantage to using the filter() function over using a list comprehension?
Hey, thanks! No advantage, list comprehension can be used interchangeably with the filter and map functions. I actually prefer list comprehension in most cases.
@@b001 Cool! Thanks for the reply.
what colours are you using? great video btw
Thanks, the theme is SynthWave 84
@@b001 ayy thank you!
is the avail_units a dictionary of dictionaries ? I think I got a little confused when I saw the extension.
You should make a video on different string formatting methods.
i use %-style im weird
What is your theme in vscode?
sometimes you learn something because you tried to name something the wrong thing (in hindsight, my list should have been called "mask" instead of "filter") and have to google it when the IDE changes your text color.
That is very interesting, never knew that existed...
Is it better/equal to a for loop with if checks?
def filter(predicate, iterable):
for item in iterable:
if predicate(item):
yield item
Or, if you prefer a one-liner:
filter = lambda p, it: (item for item in it if p(item))
That's all it does.
And now you know why only dict keys are used without their values: for loops use dict keys unless you use the dict.items() method.
@@epsi That doesnt answer my question :T
@@nyther
_Is it better/equal to a for loop with if checks?_
It is a for loop with if checks, so it's the same.
But how can the function on line 52 get a paramaters while when called on line 58 it doesn't use (arguments)? Can someone explain it for me?
That's what the filter() function does. It takes each element of the iterable and 'passes' it into the specified function.
I'm a beginner at python, is this function faster than just use a for loop to find out the data?
Can you please make a video of python automation 🙂🙂🙂🙂🙏🙏🙏
How does filter returned keys?
Please dont use
if condition:
return true
else:
return false
just use return condition 😭😭
Versus for loop?
How do you magically paste words like that? Real time or time skip?
Most likely it's reversed footage of them using Ctrl+Backspace with a voiceover.
A few videos ago he mentioned, that he writes the code, deletes parts piece by piece and later on does ctrl + z to let them reappear
what font are you using?
Why not just set the function to return a list with the value meeting the criteria and be done with it?
The filter step seems unnecessary
You didn't need the else. You could have just added return False at the end of the function without the else
actually 🤓
Что за программа на видео
What font do you use?