将嵌套列表中的元素转换为数据框

Question

我有如下嵌套列表，

 dput( list(structure(c("123.60", " on"))))

我有兴趣将此嵌套列表中的元素转换为数据框。例如，输出应如下所示。

      code      description      
      123.60    not stated as uncontrolled, with neurological manifestations
      123.50    not stated as uncontrolled, with ophthalmic manifestations
      .
      .
      .
      123.52    uncontrolled, with ophthalmic manifestations

需要帮助将这些元素转换为数据框。

Answer 1

这不完全是一个嵌套列表，而是一个命名字符向量列表。您可以对每个元素应用 as.data.frame.list，然后使用 rbind。因此，如果 x 是您的列表，那么

df <- do.call(rbind, lapply(x, as.data.frame.list, stringsAsFactors = FALSE))
## below is optional - converts character columns to appropriate type
## but will also convert some columns back to factors again
df[] <- lapply(df, type.convert) 
df
#      code                                                   description codeSystem codeSystemVersion
# 1  123.60  not stated as uncontrolled, with neurological manifestations     XAZ9CM       XAZ9CM-2012
# 2  123.50    not stated as uncontrolled, with ophthalmic manifestations     XAZ9CM       XAZ9CM-2012
# 3  123.61  not stated as uncontrolled, with neurological manifestations     XAZ9CM       XAZ9CM-2012
# 4   123.7                              peripheral circulatory disorders     XAZ9CM       XAZ9CM-2012
# 5  123.40         not stated as uncontrolled, with renal manifestations     XAZ9CM       XAZ9CM-2012
# 6  123.41         not stated as uncontrolled, with renal manifestations     XAZ9CM       XAZ9CM-2012
# 7   123.5                                     ophthalmic manifestations     XAZ9CM       XAZ9CM-2012
# 8  123.53                  uncontrolled, with ophthalmic manifestations     XAZ9CM       XAZ9CM-2012
# 9  123.52                  uncontrolled, with ophthalmic manifestations     XAZ9CM       XAZ9CM-2012
# 10  123.4                                          renal manifestations     XAZ9CM       XAZ9CM-2012

更新：你也可以

data.frame(do.call(rbind, x), stringsAsFactors=FALSE)

其他可能更有效的可能性包括

library(data.table)
rbindlist(lapply(x, as.list))

和

library(dplyr)
bind_rows(lapply(x, as.data.frame.list, stringsAsFactors=FALSE))

和（感谢 Ananda Mahto）

library(stringi)
data.frame(stri_list2matrix(x, byrow=TRUE), stringsAsFactors=FALSE)

如果您希望第一列是数字，所有这些仍然需要在第一列上进行类型转换。

另外，这个问题的数据好像已经消失了，所以这里是从编辑历史中复制过来的。

 x <- list(structure(c("123.60", " not stated as uncontrolled, with neurological manifestations",                 
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.50", " not stated as uncontrolled, with ophthalmic manifestations",  
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.61", "not stated as uncontrolled, with neurological manifestations", 
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.7", "peripheral circulatory disorders",                              
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.40", " not stated as uncontrolled, with renal manifestations",       
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.41", " not stated as uncontrolled, with renal manifestations",       
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.5", "ophthalmic manifestations",                                     
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.53", "uncontrolled, with ophthalmic manifestations",                 
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.52", " uncontrolled, with ophthalmic manifestations",                
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")), structure(c("123.4", "renal manifestations",                                          
     "XAZ9CM", "XAZ9CM-2012"), .Names = c("code", "description", "codeSystem",                                    
     "codeSystemVersion")))

将嵌套列表中的元素转换为数据框

Converting elements in a nested list to dataframe

r

list

dataframe