Conditional expressions in Python, also known as ternary operator, are used when you want to evaluate an expression based on a condition. They help to make your code shorter and more readable. The syntax is: `value_if_true if condition else value_if_false`.
Here is an example:
```
age = 15
status = ‘minor’ if age < 18 else ‘adult‘
print(status) # Output: minor
```
In this example, the variable `status` will be set to `‘minor’` if `age` is less than 18, otherwise `‘adult’`.
Python also supports the standard if-else and if-elif-else structures. Here is an example:
```
age = 20
if age < 13:
print(‘child’)
elif age < 18:
print(‘teenager’)
else:
print(‘adult’)
In this example, the code will check each condition in order (from top to bottom). If a condition is true, it will execute the associated code block and skip the rest. If none of the conditions are true, it will execute the code block in the `else` clause.
Remember that conditions are checked in order, so the first true condition found will have its body executed, skipping the rest.
