How can I use dictionary comprehension in Python to create a dictionary with keys and values?

General Discussions
1

How can I use dictionary comprehension in Python to create a dictionary with keys and values?

For example, I can use a for loop to populate a dictionary like this:

d = {}
for n in range(1, 11):
    d[n] = True  # same value for each key

However, I tried the following dictionary comprehension, but it raises a SyntaxError:

d = {}
d[i for i in range(1, 11)] = True  # raises a SyntaxError

Additionally, I would like to know if it’s possible to use dictionary comprehension in Python to set a dictionary’s keys to different values. For example, this works with a for loop:

d = {}
for n in range(1, 11):
    d[n] = n

But is there a way to express this using dictionary comprehension in Python like this:

d = {}
d[i for i in range(1, 11)] = [x for x in range(1, 11)]  # raises a SyntaxError
2

Hey

You can use dictionary comprehension in Python to assign the same value to multiple keys. For example:

d = {i: True for i in range(1, 11)}
print(d)

This creates a dictionary where keys are from 1 to 10, and all values are set to True.

Hope it was helpful to you :slight_smile:

3

If you want to assign different values to the keys, you can also use dictionary comprehension in Python. Here’s an example:

d = {i: i for i in range(1, 11)}
print(d)

This creates a dictionary where the key is i and the value is also i.

4

If you’re trying to use a nested comprehension for the dictionary’s keys and values, you can properly structure it like this:

d = {i: x for i, x in zip(range(1, 11), range(1, 11))}
print(d)

This avoids the SyntaxError and correctly assigns values from one comprehension to the dictionary, where keys are i and values are x.

Each of these solutions provides a way to use dictionary comprehension in Python efficiently.