将嵌套列表中的元素转换为数据框

Posted 2023-03-29

【中文标题】将嵌套列表中的元素转换为数据框

【英文标题】：Converting elements in a nested list to dataframe [duplicate]

【发布时间】：2015-03-11 22:11:51

【问题描述】：

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。

【问题讨论】：

尝试使用dput 以使您的问题可重现

@DavidArenburg，谢谢大卫，我现在做到了。

@Science11，您的意思是在编辑问题时删除dput 的输出吗？

【参考方案1】：

这不完全是一个 嵌套 列表，而是一个命名字符向量的列表。您可以将as.data.frame.list 应用于每个元素，然后使用rbind。所以如果x 是你的列表，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：你也可以这样做

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，所有这些仍然需要对第一列进行类型转换。

另外，这个问题的数据似乎已经消失了，所以在这里，从编辑历史中复制。

 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")))   

【讨论】：

@Science11 - 好！我添加了type.convert 以确保数字列以数字结尾，而不是字符

以前从未听说过type.convert...

@DavidArenburg - 非常简洁。它尝试将字符向量转换为适当的类型。实际上，现在我考虑一下，这里可能不合适，因为它只是再次将字符串转换回因子。哈哈

是的，谢谢，我知道如何阅读文档 :) 你在哪里找到这个宝石？

@DavidArenburg - 实际上我第一次看到它是在 Ananda Mahto 的代码中