list(base)
list()所属R语言包：base
Lists – Generic and Dotted Pairs
列表 - 通用和点对
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Functions to construct, coerce and check for both kinds of R lists.
功能建设，强制和检查的R列表两种。
用法----------Usage----------
list(...)
pairlist(...)
as.list(x, ...)
## S3 method for class 'environment'
as.list(x, all.names = FALSE, ...)
as.pairlist(x)
is.list(x)
is.pairlist(x)
alist(...)
参数----------Arguments----------
参数：...
objects, possibly named.
对象，可能命名。
参数：x
object to be coerced or tested.
反对被强迫或测试。
参数：all.names
a logical indicating whether to copy all values or (default) only those whose names do not begin with a dot.
逻辑表明是否要复制的所有值（默认）只有那些名字不以点开头。
Details
详情----------Details----------
Most lists in R internally are Generic Vectors, whereas traditional dotted pair lists (as in LISP) are available but rarely seen by users (except as formals of functions).
大多数名单在R内部通用的向量，而传统的点对列表（在LISP），但用户很少看到（formals功能除外）。
The arguments to list or pairlist are of the form value or tag = value. The functions return a list or dotted pair list composed of its arguments with each value either tagged or untagged, depending on how the argument was specified.
该参数list或pairlist形式value或tag = value的。函数返回一个列表或点对组成，它的参数列表与每个标记或未标记，取决于如何指定参数的值。
alist handles its arguments as if they described function arguments. So the values are not evaluated, and tagged arguments with no value are allowed whereas list simply ignores them. alist is most often used in conjunction with formals.
alist处理它的参数，因为如果他们描述了函数的参数。所以值不评估，并允许没有价值的标签参数，而list简单地忽略他们。 alist是最常用的formals一起。
as.list attempts to coerce its argument to a list. For functions, this returns the concatenation of the list of formal arguments and the function body. For expressions, the list of constituent elements is returned. as.list is generic, and as the default method calls as.vector(mode="list") for a non-list, methods for as.vector may be invoked. as.list turns a factor into a list of one-element factors. Attributes may be dropped unless the argument already is a list or expression. (This is inconsistent with functions such as as.character which always drop attributes, and is for efficiency since lists can be expensive to copy.)
as.list试图强迫其参数列表。对于函数，它返回串联的正式参数列表和函数体。表达式，返回的构成要素。 as.list是通用的，并作为默认方法调用as.vector(mode="list")非列表，方法as.vector可能会被调用。 as.list变成一个元素的因素列表中的一个因素。除非参数已经是一个列表或表达式的属性可能会被丢弃。 （这是不符合功能，如as.character总是下降的属性，为提高效率，是因为链表可以是昂贵的复制。）
is.list returns TRUE if and only if its argument is a list or a pairlist of length > 0. is.pairlist returns TRUE if and only if the argument is a pairlist or NULL (see below).
is.list回报TRUE如果且仅当它的参数是一个list或pairlistlength> 0。 is.pairlist回报的说法TRUE如果只是如果是1 pairlist或NULL（见下文）。
The "environment" method for as.list copies the name-value pairs (for names not beginning with a dot) from an environment to a named list. The user can request that all named objects are copied. The list is in no particular order (the order depends on the order of creation of objects and whether the environment is hashed). No enclosing environments are searched. (Objects copied are duplicated so this can be an expensive operation.) Note that there is an inverse operation, the as.environment() method for list objects.
"environment"方法as.list从一个环境复制的名称 - 值对（不是一个点开始的名字）命名列表。用户可以要求所有的命名对象被复制。这份名单是在没有特定的顺序（顺序取决于对象的创建顺序和环境是否被散列）。没有封闭的环境中进行搜索。 （对象复制是重复的，所以这可能是一项昂贵的操作。）请注意，有一个逆运算，as.environment()列表对象的方法。
An empty pairlist, pairlist() is the same as NULL. This is different from list().
一个的空pairlist，pairlist()是相同NULL。这是不同list()。
as.pairlist is implemented as as.vector(x, "pairlist"), and hence will dispatch methods for the generic function as.vector. Lists are copied element-by-element into a pairlist and the names of the list used as tags for the pairlist: the return value for other types of argument is undocumented.
as.pairlistas.vector(x, "pairlist")实施，因此将派遣泛型函数as.vector方法。名单被复制到pairlist中的元素通过元素和作为用于在pairlist标签列表的名称：对其他类型的参数的返回值是无证。
list, is.list and is.pairlist are primitive functions.
list，is.list和is.pairlist是原始的功能。
参考文献----------References----------
The New S Language. Wadsworth & Brooks/Cole.
参见----------See Also----------
vector("list", length) for creation of a list with empty components; c, for concatenation; formals. unlist is an approximate inverse to as.list().
vector("list", length)创建一个空的元件列表;c，串联;formals。 unlistas.list()是一个近似的逆。
"plotmath" for the use of list in plot annotation.
plotmath为list图注解的使用。
举例----------Examples----------
require(graphics)
# create a plotting structure[创建一个绘制结构]
pts <- list(x=cars[,1], y=cars[,2])
plot(pts)
is.pairlist(.Options) # a user-level pairlist[用户级别pairlist的]
## "pre-allocate" an empty list of length 5[＃“预分配”空列表的长度为5]
vector("list", 5)
# Argument lists[参数列表]
f <- function() x
# Note the specification of a "..." argument:[注意规范“......”参数：]
formals(f) <- al <- alist(x=, y=2+3, ...=)
f
al
## environment->list coercion[＃环境>列表胁迫]
e1 <- new.env()
e1$a <- 10
e1$b <- 20
as.list(e1)
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注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
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发表于 2012-2-16 21:06:22
