在R Studio中有558行和4列的df如何計算列中非數值的頻率

Question

RStudio的新功能。我有一個有558行和4列的df。國家和城市在DF繼續重複。

我想知道如何計算每個州有多少啤酒廠。這些列是：

Brew_ID Name    City   State 
1  NorthGate Brewing Minneapolis MN 

Answer 1

使用table（）函數。

table(df$city) 

給你每個城市的頻率計數。假設每行代表一個釀酒廠（並且您沒有州名重複的城市名稱），應該爲您提供每個城市釀酒廠的數量。

Answer 2

假設有沒有重複的行 - 你可以檢查此：

any(duplicated(df)) 

如果返回FALSE那麼你可以使用table(df$State)

例如：

Brew_ID <- c(1,2,3,4,5,6,7,8,9,10) 
    Name <- c("NorthGate Bewing", "BrewDog", "BigBrew", "Hop Head", "Yadda", "Blah Brew", "LaLa brew", "Smith's", "Harold's", "Wendy's") 
    City <- c("Minneapolis", "New York", "Phoenix", "Sacremento", "Los Angeles", "San Francisco", "Portland", "Houston", "Dallas", "Austin") 
    State <- c ("MN", "NY", "AZ","CA", "CA", "CA", "OR", "TX", "TX", "TX") 

    df <- data.frame (Brew_ID, Name, City, State) 

    table(df$State) 

返回：

AZ CA MN NY OR TX 1 3 1 1 1 3