Alteryx Foundation Micro-Credential Practice Exam

When should you use the double datatype instead of the float?

1. When precision is not a concern

2. When memory usage is critical

3. When dealing with very large or very small numbers

4. When a fixed length is needed over variable length

The correct answer is: When dealing with very large or very small numbers

Using the double datatype is particularly advantageous when dealing with very large or very small numbers due to its higher precision and range compared to float. The double datatype provides approximately 15 to 17 significant digits of precision, whereas float typically has only about 7 significant digits. This pronounced difference in precision is vital in scenarios that involve calculations requiring a high degree of accuracy, especially when working with extreme values that can easily lead to rounding errors if float is used. In contrast, the other choices focus on aspects where double might not be the best option. When precision is not an issue, float can be utilized effectively since it requires less memory and is sufficient for many applications. If memory usage is critical, float is also the more efficient choice, using 4 bytes compared to the 8 bytes used by double. Finally, the need for a fixed length over variable length suggests using a data type designed specifically for that requirement rather than floating-point types, which are inherently variable in size.