如何读取c中的csv文件,其中一些值包含百分比符号(%) [英] How to read csv file in R where some values contain the percent symbol (%)
问题描述
是否有清除/自动转换在R中以百分比(尾随%
符号)格式化的CSV值? >
以下是一些示例数据:
$ b 2.1496,8.6066,-300%
0.9170,8.0266,-775%
7.9406,0.2152,97%
4.9637,3.5237,29%
可以使用以下命令阅读:
= read.csv(Example.csv)
但是所有的%并转换为因子:
> str(junk)
'data.frame':4 obs。的3个变量:
$ actual:num 2.15 0.917 7.941 4.964
$ simulated:num 8.607 8.027 0.215 3.524
$ percent.error:因子w / 4级-300% 775%,...:1 2 4 3
但我希望它们是数字值。
read.csv有额外的参数吗?有没有办法轻松地后处理所需的列转换为数值?其他解决方案?
注意:当然在这个例子中,我可以简单地重新计算的值,但在我真正的应用程序与更大的数据文件,这是不实际的。
在R中没有百分比类型。所以你需要做一些后处理: / p>
DF < - read.table(text =actual,simulated,percent error
2.1496,8.6066,-300 %
0.9170,8.0266,-775%
7.9406,0.2152,97%
4.9637,3.5237,29%,sep =,,header = TRUE)
DF [,3]< - as.numeric(gsub(%,,DF [,3]))/ 100
#实际模拟percent.error
#1 2.1496 8.6066 -3.00
#2 0.9170 8.0266 -7.75
#3 7.9406 0.2152 0.97
#4 4.9637 3.5237 0.29
Is there a clean/automatic way to convert CSV values formatted with as percents (with trailing %
symbol) in R?
Here is some example data:
actual,simulated,percent error
2.1496,8.6066,-300%
0.9170,8.0266,-775%
7.9406,0.2152,97%
4.9637,3.5237,29%
Which can be read using:
junk = read.csv("Example.csv")
But all of the % columns are read as strings and converted to factors:
> str(junk)
'data.frame': 4 obs. of 3 variables:
$ actual : num 2.15 0.917 7.941 4.964
$ simulated : num 8.607 8.027 0.215 3.524
$ percent.error: Factor w/ 4 levels "-300%","-775%",..: 1 2 4 3
but I would like them to be numeric values.
Is there an additional parameter for read.csv? Is there a way to easily post process the needed columns to convert to numeric values? Other solutions?
Note: of course in this example I could simply recompute the values, but in my real application with a larger data file this is not practical.
There is no "percentage" type in R. So you need to do some post-processing:
DF <- read.table(text="actual,simulated,percent error
2.1496,8.6066,-300%
0.9170,8.0266,-775%
7.9406,0.2152,97%
4.9637,3.5237,29%", sep=",", header=TRUE)
DF[,3] <- as.numeric(gsub("%", "",DF[,3]))/100
# actual simulated percent.error
#1 2.1496 8.6066 -3.00
#2 0.9170 8.0266 -7.75
#3 7.9406 0.2152 0.97
#4 4.9637 3.5237 0.29
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