What's the pythonic method of doing multiple ors?

ghz 昨天 ⋅ 3 views

In Python, there are a few ways to express multiple or conditions. The pythonic approach tends to favor readability and conciseness. The most common and idiomatic methods for doing multiple or conditions are as follows:

1. Using Chained or Statements

The most straightforward and readable way to express multiple or conditions is to chain them together using or. This is both simple and efficient.

Example:

if condition1 or condition2 or condition3:
    # do something

This works well when the conditions are simple and don't require any additional logic.

2. Using any() with a List or Tuple

If you have many conditions to check, using the built-in any() function with a list (or tuple) of conditions is a very clean and pythonic approach. This makes it easy to manage a variable number of conditions and avoids having to repeat or for every condition.

Example:

if any([condition1, condition2, condition3]):
    # do something
  • The any() function returns True if at least one of the conditions evaluates to True.
  • This is especially useful when dealing with conditions that can be expressed as elements in a list or iterable.

Example with Tuple:

if any((condition1, condition2, condition3)):
    # do something

3. Using any() with Generators (for Large or Dynamic Conditions)

For large or dynamically generated lists of conditions, it's even more memory-efficient to use a generator expression with any(), which avoids creating an intermediate list or tuple.

Example:

if any(condition() for condition in [condition1, condition2, condition3]):
    # do something

Here, condition could be a callable, and condition() could return boolean values dynamically.

4. Using set() for Unique Conditions

If your conditions are more complex and you want to ensure that you're only considering unique conditions (i.e., avoiding duplication), you could use a set. This would be useful when conditions are complex and you want to check them only once, but avoid redundant checks.

Example:

if any({condition1, condition2, condition3}):
    # do something
  • The set() removes duplicates, so if condition1 and condition2 are identical, they won't be checked twice.

Which Method to Choose?

  • Simple or chaining is best when you have a small number of straightforward conditions.
  • any() with a list or tuple is more readable and scales better for a moderate number of conditions.
  • any() with a generator is ideal for large sets of dynamic conditions, or when conditions need to be evaluated lazily.
  • set() is useful when conditions may contain duplicates and you want to check them only once.

Example of All Methods Combined

# Example conditions
condition1 = True
condition2 = False
condition3 = False

# Using chained or statements
if condition1 or condition2 or condition3:
    print("At least one condition is True")

# Using any() with a list
if any([condition1, condition2, condition3]):
    print("At least one condition is True")

# Using any() with a generator expression
if any(condition() for condition in [condition1, condition2, condition3]):
    print("At least one condition is True")

# Using a set (removes duplicates)
if any({condition1, condition2, condition3}):
    print("At least one condition is True")

In this case, using any() or chaining or are both clear and idiomatic. The use of any() is typically more readable and scales better when you need to handle many conditions.