13.11. Sass list function

Function	Description & example
`append(list, value, [separator])`	Add a single value value to the end of the list. Separator is a delimiter and is automatically detected by default, or specified as a comma or space. Example: append ((a b c), d) result: a b c d append ((a b c), (d), comma) result: a, b, c, d
`index(list, value)`	Returns the index position of the element value in the list. Example: index (a b c, b) result: 2 index (a b c, f) result: null
`is-bracketed(list)`	Determine whether there are brackets in the list Example: is-bracketed ( [a b c] ) result: true is-bracketed (a b c) result: false
`join(list1, list2, [separator, bracketed])`	Merge the two lists and add the list list2 to the end of the list list1. Separator is a delimiter and is automatically detected by default, or specified as a comma or space. By default, bracketed automatically detects whether there are square brackets, which can be set to true or false. Example: join (a b c, d e f) result: a b c d e f join ((a b c), (d e f), comma) result: a, b, c, d, e, f join (a b c, d e f, $bracketed: true) result: [a b c d e f]
`length(list)`	Returns the length of the list Example: length (a b c) result: 3
`list-separator(list)`	Returns the delimiter type of a list. It can be a space or a comma. Example: list-separator (a b c) result: “space” list-separator (a, b, c) result: “comma”
`nth(list, n)`	Gets the value of item n. Example: nth (a b c, 3) result: C
`set-nth(list, n, value)`	Set the value of item n of the list to value. Example: set-nth (a b c, 2, x) result: a x c
`zip(lists)`	Reassemble multiple lists into a new multi-dimensional list with the same index values. Example: zip (1px 2px 3px, solid dashed dotted, red green blue) result: 1px solid red, 2px dashed green, 3px dotted blue

Function

Description & example

append(list, value, [separator])

Add a single value value to the end of the list. Separator is a delimiter and is automatically detected by default, or specified as a comma or space.

Example: append ((a b c), d) result: a b c d append ((a b c), (d), comma) result: a, b, c, d

index(list, value)

Returns the index position of the element value in the list.

Example: index (a b c, b) result: 2 index (a b c, f) result: null

is-bracketed(list)

Determine whether there are brackets in the list

Example: is-bracketed ( [a b c] ) result: true is-bracketed (a b c) result: false

join(list1, list2, [separator, bracketed])

Merge the two lists and add the list list2 to the end of the list list1. Separator is a delimiter and is automatically detected by default, or specified as a comma or space. By default, bracketed automatically detects whether there are square brackets, which can be set to true or false.

Example: join (a b c, d e f) result: a b c d e f join ((a b c), (d e f), comma) result: a, b, c, d, e, f join (a b c, d e f, $bracketed: true) result: [a b c d e f]

length(list)

Returns the length of the list

Example: length (a b c) result: 3

list-separator(list)

Returns the delimiter type of a list. It can be a space or a comma.

Example: list-separator (a b c) result: “space” list-separator (a, b, c) result: “comma”

nth(list, n)

Gets the value of item n.

Example: nth (a b c, 3) result: C

set-nth(list, n, value)

Set the value of item n of the list to value.

Example: set-nth (a b c, 2, x) result: a x c

zip(lists)

Reassemble multiple lists into a new multi-dimensional list with the same index values.

Example: zip (1px 2px 3px, solid dashed dotted, red green blue) result: 1px solid red, 2px dashed green, 3px dotted blue

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.