Question

我有一个农贸市场数据集，其中一列是“MarketName”（第2列），其中一列是“WIC”（第21栏）。如果WIC列= Y，我写了一个函数来检索市场名称。我的输出应该是2,207个名称的列表，但是我得到8,144行的输出，因为对于WIC列= N的行，我的输出显示NA 。有45列和8,144行，但这里是一个只有两列的假数据集

MarketName <- c("Union Springs Famers Market","Union Square Farmers Market", "Union Square Greenmarket", "Union Street Farmers Market", "Unity Market Day Farmers", "University Farmers Market") 
WIC <- c("Y","N","N","N","Y","Y")
data3 <- data.frame(MarketName, WIC)
data3$MarketName <- as.character(data3$MarketName)
data3$WIC <- as.character(data3$WIC)

这是我的功能（可能是问题？）

marketacceptWIC <- function(mydf)
{
    market <- 0
    for(i in 1:length(data3$WIC))
    {
        if(data3[i,2] == "Y")
            market[i] <- data3[i,1]
    }
    return(market)
}

这是我得到的输出样本

[1] "Union Springs Famers Market" NA                            NA                            NA                           
[5] "Unity Market Day Farmers"    "University Farmers Market"

我想要的只是接受WIC的农贸市场清单

[1] "Union Springs Farmers' Market"                                                       
[2] "Unity Market Day Farmers"                                                         
[3] "University Farmers Market"

Answer 1

我认为你不需要for循环。尝试在WIC列上进行子集化。如果您只需要MarketName列，那么

data3[data3$WIC == "Y", ]$MarketName

[1] "Union Springs Famers Market" "Unity Market Day Farmers"    "University Farmers Market"

函数根据R

1 个答案: