How Can I Efficiently Create Lists with Repeated Elements Without List Comprehensions?

Efficiently Generating Lists with Single Repeated Elements

Suppose you need to create multiple lists, each containing a specific element e repeated a varying number of times. How can you accomplish this without employing list comprehensions for each list?

Solution Using List Multiplication

Apart from list comprehensions, you can create the lists using list multiplication. Simply repeat the element e n times to obtain a list of length n:

[e] * n

Additional Considerations

Note that if e is an empty list, this approach will create a list with n references to the same empty list, not n independent empty lists.

Performance Testing

Initial performance testing may indicate that the repeat function is faster than list multiplication. However, this is misleading because repeat does not actually create a list; it creates an iterable that can be converted to a list if needed.

When comparing the actual creation of lists, list multiplication is significantly faster than converting repeat iterables to lists. Therefore, for the purpose of creating lists, it is recommended to use list multiplication:

[e] * n

The above is the detailed content of How Can I Efficiently Create Lists with Repeated Elements Without List Comprehensions?. For more information, please follow other related articles on the PHP Chinese website!