使用 Fread 读取带有双引号和逗号的字段时出错

Question

我有一个包含 19 列 character/numeric 数据的大型 csv 文件。

在运行 fread 后，我收到一条错误消息，说我的数字列之一正在转换为字符，因为该字段具有值 ""。然后我在文本编辑器中打开我的数据，找到了问题的根源。在一行中，字符列显示为：

"""PARENTS"", ""Y.M."", AND ""EXPECTING"""

对应的字符串：

"PARENTS", "Y.M.", AND "EXPECTING"

作为：

第一个引号是字符串保护符
第2至第6对引号为单引号
最后一个引号是字符串保护器的收盘价。

据我之前所见，fread 会读取此转换 "" 到 \"。这种情况下的问题是该字符串还包含逗号。这些被解释为定界符，这打乱了我的列顺序并将后面的字符列推入我的数字字段。

有没有办法阻止它，或者我应该使用另一个软件包？

注意：我四处寻找解决方案，感觉 "" + fread 是令人沮丧的根源，但还没有看到添加逗号复杂性的示例。

转载：

将以下内容放入 txt 文件中：

"A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S"
"168263291","Gruner & Jahr Printing and Publishing Company","Parents Ym and Expecting","""PARENTS"", ""Y.M."", AND ""EXPECTING""",0,0,3,"73130201","055302756","Quad/Graphics Inc.","013034588","02","093671063","000000000","Unclassified","94133","San Francisco","CALIFORNIA","UNITED STATES"

读取数据：

DT <- fread("myfile.csv",colClasses = c(rep("Character",5),
                                        rep("numeric",2),
                                        rep("character",12))
            ,sep = ",")

Answer 1

在当前开发 v1.9.5 中对 fread() 进行了最近的修复，这就是我得到的：

require(data.table) #v1.9.5+
fread('A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S
"168263291","Gruner & Jahr Printing and Publishing Company","Parents Ym and Expecting","""PARENTS"", ""Y.M."", AND ""EXPECTING""",0,0,3,"73130201","055302756","Quad/Graphics Inc.","013034588","02","093671063","000000000","Unclassified","94133","San Francisco","CALIFORNIA","UNITED STATES"')

#            A                                             B                        C
# 1: 168263291 Gruner & Jahr Printing and Publishing Company Parents Ym and Expecting
                                          D E F G        H         I
# 1: ""PARENTS"", ""Y.M."", AND ""EXPECTING"" 0 0 3 73130201 055302756
                    J         K  L         M         N            O     P
# 1: Quad/Graphics Inc. 013034588 02 093671063 000000000 Unclassified 94133
               Q          R             S
# 1: San Francisco CALIFORNIA UNITED STATES

fread() 更稳健地处理嵌入引号，默认去除空格（新 strip.white 参数，默认=TRUE），并且还获得了 encoding 参数。请参阅项目页面上的 README 以获取最新消息。

如果您的问题仍未解决（在此处或在项目页面上）并提供可重现的示例，请告诉我们。

使用 Fread 读取带有双引号和逗号的字段时出错

Error reading Field with Double Quotes and Commas using Fread

r

data.table