Plurals

As you saw in the preceding section, plurals of inspectors are easy to create, typically by adding an 's' to the end of the name. For example, substring is singular, substrings is plural:

But a plural inspector doesn’t have to return multiple values:

Although the result is a plural substring type, there is only a single value. As you saw in the last section, a plural expression can return no value at all, without incurring an error.

substrings separated by " " whose (it contains "z") of "a short string"

This returns no values, but no error either. So it’s important to remember that plurality is a property of the expression itself, not necessarily the results.

Furthermore, there are restraints on singular expressions. Whereas a plural can return zero, one or more values, a singular expression is expected to return a single value. For example:

You should be expecting a solitary value like this as a result of inspector. However, the following returns an error:

This is because there are two words containing 's', and this expression is looking for a singular value. While two is too much, zero is not enough:

If you're certain of retrieving a solitary value, use the singular version. Otherwise, for greater flexibility, use the plural. As a practical example, you can find a single folder like this:

But as you can see, even though it returns an answer, it also generates an error. This is because there are multiple folders in the specified location, and this command only retrieves the first one. To see the complete list, you must use the plural version:

You can explicitly create plurals using a semicolon ; to separate the items. These are called "collections".

Notice that plurals must be the same type, or you will generate an error: