Note that this site is in currently in version 1.0.0-alpha.   Some functionality may be limited.

Terms starting with L

Layers are “containers” of the data in QGIS. On the map view, layers can be imagined as transparent film sheets that are laid one over another. With the exception of raster layers, each layer contains an Attribute Table, that is, a series of features that in turn have their own attributes. Vector layers can only contain one type of vectors, be it: points, lines or polygons.

A process of collapsing words in an attempt to reduce the number of words, and get a realistic understanding of the meaning of a text. Lemmatization references the word and finds the appropriate root and can therefore take longer than other processes of collapsing words. See “stemming” in this glossary for another process of collapsing words in a corpus.

len() is a function that calculates the length of the object within the parenthesis. For a string, it will count the number of characters: len("hello") will return 5, and len("hi there") will return 8, because it counts blank spaces. For a list, len() will count the number of list items:

>>> groceries = ["berries", "bananas", "oat milk", "eggs", "spinach", "bell peppers", "ice cream", "frozen pizza", "floss", "hand soap"]
>>> len(groceries)

The number of unique words per total words; a good metric to approximate lexical diversity—the range of vocabulary an author uses.

A Python library is a reusable piece of code / sets of instructions that you use in your script.

A list is a data type, like string, integer, float, and Boolean. A list holds items in a sequence, separated by commas and contained within square brackets. They can hold different types of data, like strings, integers, floats, etc. Items within a list can be accessed by list indexing or slicing.

List indexing is a foundational tool for working with lists. It allows one to access items from a list by specifying the item according to its location within the list. The item location is represented the number within brackets. In a list index, the count starts at 0, so the first item is accessed by list[0] and the second item by list[1], the third item by list[2], and so on.

lower() is a string method for making all of the letters within a string into lowercase letters. It uses the dot syntax . for creating the expression. For example, “HEllO” can be transformed into lowercase by running "HELLO".lower(), which will return the string 'hello'.