List

Lists in Risor behave very similarly to lists in Python. Methods and indexing on lists are the primary way to interact with these objects. A list can store objects of any types, including a mix of types in one list.

>>> l := ["a", 1, 2]
["a", 1, 2]
>>> l.append("tail")
["a", 1, 2, "tail"]

Container Operations

>>> l := ["a", "b", "c"]
["a", "b", "c"]
>>> len(l)
3
>>> "c" in l
true
>>> "d" in l
false
>>> l[2]
"c"
>>> l[2] = "d"
>>> l
["a", "b", "d"]
>>> l[1:]
["b", "d"]
>>> l[:1]
["a"]

Related Built-ins

list(container)

Returns a new list populated with items from the given container. If a list is provided, a shallow copy of the list is returned. It is also commonly used to convert a set to a list.

>>> s := {"a", "b", "c"}
{"a", "b", "c"}
>>> list(s)
["a", "b", "c"]

Methods

list.append(x)

Adds x to the end of the list.

list.clear()

Empties all items from the list.

list.copy()

Returns a shallow copy of the list.

list.count(x)

Returns a count of how many times x is found in the list.

list.extend(x)

Adds all items contained in x to the end of the list.

list.index(x)

Returns the first index of x in the list, or -1 if not found.

list.insert(index, x)

Inserts x into the list at the specified index.

list.pop(index)

Removes the item at the given index from the list.

list.remove(x)

Removes the first occurence of x in the list.

list.reverse()

Reverses the list in place.

list.sort()

Sorts the list in place.

list.map(func)

Returns a transformed list, in which the given function is applied to each list item.

list.filter(func)

Returns a transformed list, in which the given function returns true for items that should be added to the output list.

list.each(func)

Calls the supplied function once with each item in the list.