What is the Difference Between & and &&?
🆚 Go to Comparative Table 🆚The main difference between the & and && operators lies in their evaluation of conditional statements:
- Bitwise vs. Logical: The
&operator is both a logical and a bitwise operator, whereas the&&operator is only a logical operator. The bitwise AND operator (&) works on bits and performs "bit by bit" operations, while the logical AND operator (&&) operates on Boolean expressions. - Short-circuit evaluation: The
&&operator is a short-circuit operator, meaning it only checks the left-hand side of the conditional statement. If the left-hand side results in FALSE, the right-hand side of the expression is not evaluated because the result is already known to be FALSE. The&operator, on the other hand, evaluates both sides of the expression.
In summary, the & operator is used for both logical and bitwise operations, evaluating both sides of the expression, while the && operator is used only for logical operations and evaluates only the left-hand side of the expression using short-circuit evaluation.
Comparative Table: & vs &&
The main difference between the logical AND operators and and && lies in their evaluation behavior and performance. Here's a summary of their differences:
| Operator | Evaluation Behavior | Performance |
|---|---|---|
and |
Perform element-wise comparisons in much the same way as arithmetic operators. | Slower than &&. |
&& |
Evaluate left to right examining only the first element of each vector, with evaluation proceeding only until the result is determined. | Faster than and. |
In R, the and operator performs element-wise comparisons along the vectors, which can be slower than the && operator. The && operator evaluates left to right, stopping as soon as the result is determined, making it more efficient. For example, comparing two vectors x > 1 & x < 3 with the and operator takes longer than x > 1 && x < 3 with the && operator.