list 将多个数据框放入列表中（智能方式）
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Put multiple data frames into list (smart way)
提问by Martin Petri Bagger
Is it possible to put a lot of data frames into a list in some easy way? Meaning instead of having to write each name manually like the following way:
是否可以以某种简单的方式将大量数据框放入一个列表中？意思是不必像下面这样手动编写每个名称：
list_of_df <- list(data_frame1,data_frame2,data_frame3, ....)
I have all the data frames loaded into my work space. I am going to use the list to loop over all the data frames (to perform the same operations on each data frame).
我已将所有数据框加载到我的工作空间中。我将使用列表遍历所有数据帧（对每个数据帧执行相同的操作）。
回答by Arun
You can use ls()with getas follows:
您可以使用ls()具有get如下：
l.df <- lapply(ls(), function(x) if (class(get(x)) == "data.frame") get(x))
This'll load all data.frames from your current environment workspace.
这将从您当前的环境工作区加载所有 data.frames。
Alternatively, as @agstudy suggests, you can use pattern to load just the data.frames you require.
或者，正如@agstudy 建议的那样，您可以使用模式来加载data.frame您需要的s。
l.df <- lapply(ls(pattern="df[0-9]+"), function(x) get(x))
Loads all data.frames in current environment that begins with dffollowed by 1 to any amount of numbers.
加载data.frame当前环境中以df1开头的所有s到任意数量的数字。
回答by Paul Hiemstra
By far the easiest solution would be to put the data.frame's into a list where you create them. However, assuming you have a character list of object names:
到目前为止，最简单的解决方案是将data.frame's 放入创建它们的列表中。但是，假设您有一个对象名称的字符列表：
list_df = lapply(list_object_names, get)
where you could construct you list like this (example for 10 objects):
您可以在其中构建这样的列表（例如 10 个对象）：
list_object_names = sprintf("data_frame%s", 1:10)
or get all the objects in your current workspace into a list:
或者将当前工作区中的所有对象放入一个列表中：
list_df = lapply(ls(), get)
names(list_df) = ls()
回答by agstudy
You can use lswith a specific pattern for example. For example:
例如，您可以使用ls特定模式。例如：
some data.frames:
一些数据框架：
data.frame1 <- data.frame()
data.frame2 <- data.frame()
data.frame3 <- data.frame()
data.frame4 <- data.frame()
list(ls(pattern='data.fra*'))
[[1]]
[1] "data.frame1" "data.frame2" "data.frame3" "data.frame4"
