data.table :: fread中的dec参数 [英] dec argument in data.table::fread
问题描述
我使用 fread
从 data.table
加载csv文件。但是我的csv文件使用 dec =,
作为小数分隔符( 1.23
将 1,23
)。与 read.csv
不同, dec
不是允许的参数。
I am using fread
from data.table
to load csv files. However my csv files uses dec=","
as a decimal-separator (1.23
will be 1,23
). Unlike in read.csv
it seems that dec
is not an allowed parameter.
R) args(fread)
function (input = "test.csv", sep = "auto", sep2 = "auto", nrows = -1,
header = "auto", na.strings = "NA", stringsAsFactors = FALSE,
verbose = FALSE, autostart = 30)
你看到一个工作(一个R选项设置可能),将使我能够使用 fread
(它是如此快得多,它节省了我很多时间)?
Do you see a work around (a R option to set may be) that will enable me to use fread
(it is so much faster that it saves me a lot of time)?
PS: colClasses
尚未实现,所以 setAs
不能像此帖中使用
PS: colClasses
is not yet implemented so setAs
cannot be used like in this post
推荐答案
2014年10月更新:现在在v1.9.5
Update Oct 2014 : Now in v1.9.5
fread
现在接受 dec =','
十进制分隔符),#917 。新的段落已添加到?fread
。如果你位于使用 dec =','
的国家,那么它应该工作。如果没有,你将需要阅读段落一个额外的步骤。如果它以某种方式断开 dec ='。'
,这个新功能可以通过选项(datatable.fread.dec.experiment = FALSE)
。
fread
now acceptsdec=','
(and other non-'.' decimal separators), #917. A new paragraph has been added to?fread
. If you are located in a country that usesdec=','
then it should just work. If not, you will need to read the paragraph for an extra step. In case it somehow breaksdec='.'
, this new feature can be turned off withoptions(datatable.fread.dec.experiment=FALSE)
.
上一个答案...
Previous answer ...
Matt Dowle发现了一个使用语言环境的好工作。
第一个 sessionInfo
Matt Dowle found a nice work-around with locales.
First my sessionInfo
sessionInfo()
R version 2.15.2 (2012-10-26)
Platform: i386-w64-mingw32/i386 (32-bit)
locale:
[1] LC_COLLATE=French_France.1252 LC_CTYPE=French_France.1252 LC_MONETARY=French_France.1252 LC_NUMERIC=C
[5] LC_TIME=C
...
尝试以下显示了罪魁祸首:
Trying the following shows the culprit:
Sys.localeconv()["decimal_point"]
decimal_point
"."
尝试设置LC_NUMERIC在Ubuntu(Matthew)和WinXP(me)上工作
Trying to set the LC_NUMERIC worked on Ubuntu(Matthew) and WinXP(me)
Sys.setlocale("LC_NUMERIC", "French_France.1252")
[1] "French_France.1252"
Message d'avis :
In Sys.setlocale("LC_NUMERIC", "French_France.1252") :
changer 'LC_NUMERIC' peut résulter en un fonctionnement étrange de R
行为很好,更改为:
DT = fread("A,B\n3,14;123\n4,22;456\n",sep=";")
str(DT)
Classes ‘data.table’ and 'data.frame': 2 obs. of 2 variables:
$ V1: num 3.14 4.22
$ V2: int 123 456
。
DT = fread("A,B\n3.14;123\n4.22;456\n",sep=";")
str(DT)
Classes ‘data.table’ and 'data.frame': 2 obs. of 2 variables:
$ V1: chr "3.14" "4.22"
$ V2: int 123 456
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