general coding

Question 1

what does dict.get do?

Answer 1

Using get() with an existing key

It’s a safer way to retrieve values from a dictionary that helps avoid KeyError exceptions.

The basic syntax is: dict.get(key, default_value)

Here’s a simple example:

```python
user = {“name”: “Alice”, “age”: 30}

print(user.get(“name”)) # Output: “Alice”

print(user.get(“email”)) # Output: None

print(user.get(“email”, “no email found”)) # Output: “no email found”
~~~

The key difference between dict.get() and direct access using square brackets (dict[key]) is:
- dict[key] raises a KeyError if the key doesn’t exist
- dict.get(key) returns None if the key doesn’t exist
- dict.get(key, default) returns the specified default value if the key doesn’t exist

This makes get() particularly useful when you want to handle missing keys gracefully without try/except blocks.

Question 2

How can I turn all zeros in a 2d numpy array to 1 and all non zero elements to 1 with numpy function

Answer 2

Method 1: Using where()

Here are two simple ways to do this using NumPy functions:

```python
import numpy as np

result = np.where(arr == 0, 1, 0)

result = (arr == 0).astype(int)
~~~

Both methods will achieve the same result. For example:

```python
arr = np.array([[0, 5, 0],
[3, 0, 2],
[0, 1, 4]])

# [[1, 0, 1],
# [0, 1, 0],
# [1, 0, 0]]
~~~

The where() method is often more readable, while the logical operator method might be slightly more performant. Choose whichever style you prefer!