Returns a substring of a string, starting at a specified index position and including the specified number of characters. The index is zero-based.
$substrhas the following syntax:
The arguments can be any valid expression as long as the first argument resolves to a string, and the second and third arguments resolve to integers. For more information on expressions, see Expressions.
<start> is a negative number,
$substr returns an empty string
<length> is a negative number,
$substr returns a substring that starts at the specified index and includes the rest of the string.
$substr only has a well-defined behavior for strings of ASCII characters.
inventory collection with the following documents:
The following operation uses the
$substr operator to separate the
quarter value into a
yearSubstring and a
The operation returns the following results: