Wait, why did all functions return 2?
The lambdas don’t capture the value of
This is called late binding and can cause unexpected behavior when creating closures inside loops.
So as a quick tip, Bind the current value at definition time using a default argument(like shown in the second image) Then each lambda remembers its own
The lambdas don’t capture the value of
i at each loop iteration, they capture the variable itself. By the time you call the functions, the loop has finished, and i is left at its final value, 2.This is called late binding and can cause unexpected behavior when creating closures inside loops.
So as a quick tip, Bind the current value at definition time using a default argument(like shown in the second image) Then each lambda remembers its own
i value independently.❤2
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Anonymous Quiz
30%
list()
45%
[ ]
7%
Same speed
18%
Depends on list size
Anonymous Quiz
18%
set
15%
dict
57%
array
10%
tuple
Feels off?
It's because all your objects share one variable (without you realizing it)
At first glance, it seems like every object should start fresh, right? But in this case, count is a class variable, which means it’s shared by all instances of the class.
Every time you create a new
If your goal is to give each object its own value, define it like this instead
Now, each instance has its own count, stored on the object itself . no sharing, no surprises.
It's because all your objects share one variable (without you realizing it)
At first glance, it seems like every object should start fresh, right? But in this case, count is a class variable, which means it’s shared by all instances of the class.
Every time you create a new
Counter(), you’re actually incrementing the same shared variable not something unique to each object.If your goal is to give each object its own value, define it like this instead
class Counter:
def __init__(self):
self.count = 1
Now, each instance has its own count, stored on the object itself . no sharing, no surprises.
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Looks neat, right? But let’s slow down.
The
The starred variable always gets a list, and it can be empty so plan accordingly when unpacking, especially in function arguments or loops.
For example: Consider the following code
No error, but
The
*b syntax is called extended iterable unpacking. It grabs everything in the middle of the list, leaving the first item (a) and the last (c) outside the star. This pattern is super handy, but can also behave unexpectedly if you assume it’ll grab just one item or not consider the structure of the data.The starred variable always gets a list, and it can be empty so plan accordingly when unpacking, especially in function arguments or loops.
For example: Consider the following code
x, *y = [42]
print(y) # []
No error, but
y is just an empty list! Unpacking doesn’t always fill every name the way you might guess.❤1👍1