mirror of
https://github.com/satwikkansal/wtfpython
synced 2024-11-24 03:54:25 +01:00
added new example
This commit is contained in:
parent
27b66b4f31
commit
3709c10cd4
44
README.md
vendored
44
README.md
vendored
@ -59,6 +59,7 @@ So, here we go...
|
||||
+ [▶ The disappearing variable from outer scope](#-the-disappearing-variable-from-outer-scope)
|
||||
+ [▶ The mysterious key type conversion](#-the-mysterious-key-type-conversion)
|
||||
+ [▶ Let's see if you can guess this?](#-lets-see-if-you-can-guess-this)
|
||||
+ [▶ Copy DEEP without deep copy](#-copy-deep-without-deep-copy)
|
||||
* [Section: Slippery Slopes](#section-slippery-slopes)
|
||||
+ [▶ Modifying a dictionary while iterating over it](#-modifying-a-dictionary-while-iterating-over-it)
|
||||
+ [▶ Stubborn `del` operation](#-stubborn-del-operation)
|
||||
@ -1898,6 +1899,49 @@ a, b = a[b] = {}, 5
|
||||
True
|
||||
```
|
||||
|
||||
---
|
||||
### ▶ Copy DEEP without deep copy
|
||||
|
||||
```py
|
||||
>>> new_list = [1,2,4,5,6]
|
||||
>>> new_list_copy = new_list
|
||||
>>> new_list_copy.append(10)
|
||||
```
|
||||
|
||||
**Output:**
|
||||
```py
|
||||
>>> new_list
|
||||
[1, 2, 4, 5, 6, 10]
|
||||
>>> new_list_copy
|
||||
[1, 2, 4, 5, 6, 10]
|
||||
```
|
||||
***But....***
|
||||
|
||||
```py
|
||||
>>> new_list = [1,2,4,5,6]
|
||||
>>> new_list_dcopy = new_list[:]
|
||||
>>> new_list_dcopy.append(20)
|
||||
```
|
||||
|
||||
**Output:**
|
||||
```py
|
||||
>>> new_list
|
||||
[1, 2, 4, 5, 6]
|
||||
>>> new_list_dcopy
|
||||
[1, 2, 4, 5, 6, 20]
|
||||
```
|
||||
|
||||
_What did just happen then?_
|
||||
|
||||
#### 💡 Explanation:
|
||||
|
||||
In Python, we have concept of [deep copy](https://docs.python.org/3/library/copy.html) and [shallow copy](https://docs.python.org/3/library/copy.html).
|
||||
In the first example, `new_list` is the original list and `new_list_copy` is the shallow copy of the original list. As a result changes made to the copied list has reflected back to the original list.
|
||||
|
||||
The second example shows that `new_list_dcopy` is a deep copy of the original list `new_list`, where changes made in the deep copied list doesn't reflect back to the original list.
|
||||
|
||||
One can easily deep copy a list without using the *copy.deepcopy(new_list)* just by using `slicing` , where any changes made to the copied list won't reflect back to the original list. Trick!!
|
||||
|
||||
---
|
||||
---
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user