fread，data.table中的小数点设置 [英] decimal point setting in fread, data.table

问题描述

我想使用data.table中的fread，但会收到与小数点有关的警告[这里是‘，’而不是’。]。通常我使用'。'，但是在某些情况下，我必须使用'，'作为小数点导入文件。

I would like to use fread from data.table, but get a warning related to the decimal point [here a ',' instead of a '.']. Normally I use '.', but in some cases the file I have to import files with ',' as decimal point.

在read.csv中，我可以设置小数点分隔符：

In read.csv I can set the decimal point separator:

df <- read.csv("mydata.csv", sep=";", dec=",")

如何在data.table的fread函数中执行此操作？与

How can I do this in the fread function in data.table? with

df=fread('mydata.csv',sep=';')

我收到警告消息：

Warning message:
In fread("mydata.csv",  :
Bumped column 7 to type character on data row 86, field contains '4,5'. 

，其中4,5是在read.csv中正确读取为'4.5'并且带有sep ='的值。

, where 4,5 is the value the would have been read in correctly as '4.5' with sep=',' in read.csv.

sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8   
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C  

推荐答案

2014年10月更新：现在在v1中。 9.5

Update Oct 2014 : Now in v1.9.5

fread 现在接受 dec ='，' （和其他非。小数点分隔符），＃917 。 ？fread 中添加了一个新段落。如果您位于使用 dec =’，’的国家/地区，那么它应该可以正常工作。如果没有，您将需要阅读该段落以执行额外的步骤。如果它以某种方式破坏了 dec ='。'，可以使用 options（datatable.fread.dec.experiment = FALSE）关闭此新功能。 。

fread now accepts dec=',' (and other non-'.' decimal separators), #917. A new paragraph has been added to ?fread. If you are located in a country that uses dec=',' then it should just work. If not, you will need to read the paragraph for an extra step. In case it somehow breaks dec='.', this new feature can be turned off with options(datatable.fread.dec.experiment=FALSE).

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由于您使用的是Linux，因此使用 data.table 1.8.11您可以执行以下操作：

Since you're on Linux, using data.table 1.8.11 you can do the following:

fread("sed 's/,/./g' yourfile", sep = ";")

（实际上，我认为您甚至不需要指定 sep 此处）

(actually I don't think you even need to specify sep here)

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