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因子是用于對(duì)數(shù)據(jù)進(jìn)行分類并將其存儲(chǔ)為級(jí)別的數(shù)據(jù)對(duì)象。 它們可以存儲(chǔ)字符串和整數(shù)。 它們?cè)诰哂杏邢迶?shù)量的唯一值的列中很有用。 像“男性”,“女性”和True,F(xiàn)alse等。它們?cè)诮y(tǒng)計(jì)建模的數(shù)據(jù)分析中很有用。
使用
factor()函數(shù)通過將向量作為輸入創(chuàng)建因子。
例
# Create a vector as input.
data <- c("East","West","East","North","North","East","West","West","West","East","North")
print(data)
print(is.factor(data))
# Apply the factor function.
factor_data <- factor(data)
print(factor_data)
print(is.factor(factor_data))
當(dāng)我們執(zhí)行上面的代碼,它產(chǎn)生以下結(jié)果 -
[1] "East" "West" "East" "North" "North" "East" "West" "West" "West" "East" "North" [1] FALSE [1] East West East North North East West West West East North Levels: East North West [1] TRUE
數(shù)據(jù)幀的因子
在創(chuàng)建具有文本數(shù)據(jù)列的任何數(shù)據(jù)框時(shí),r語言將文本列視為分類數(shù)據(jù)并在其上創(chuàng)建因子。
# Create the vectors for data frame.
height <- c(132,151,162,139,166,147,122)
weight <- c(48,49,66,53,67,52,40)
gender <- c("male","male","female","female","male","female","male")
# Create the data frame.
input_data <- data.frame(height,weight,gender)
print(input_data)
# Test if the gender column is a factor.
print(is.factor(input_data$gender))
# Print the gender column so see the levels.
print(input_data$gender)
嘗試一下
當(dāng)我們執(zhí)行上面的代碼,它產(chǎn)生以下結(jié)果 -
height weight gender 1 132 48 male 2 151 49 male 3 162 66 female 4 139 53 female 5 166 67 male 6 147 52 female 7 122 40 male [1] TRUE [1] male male female female male female male Levels: female male
更改級(jí)別順序
可以通過使用新的等級(jí)次序再次應(yīng)用因子函數(shù)來改變因子中的等級(jí)的順序。
data <- c("East","West","East","North","North","East","West","West","West","East","North")
# Create the factors
factor_data <- factor(data)
print(factor_data)
# Apply the factor function with required order of the level.
new_order_data <- factor(factor_data,levels = c("East","West","North"))
print(new_order_data)
當(dāng)我們執(zhí)行上面的代碼,它產(chǎn)生以下結(jié)果 -
[1] East West East North North East West West West East North Levels: East North West [1] East West East North North East West West West East North Levels: East West North
生成因子級(jí)別
我們可以使用gl()函數(shù)生成因子級(jí)別。 它需要兩個(gè)整數(shù)作為輸入,指示每個(gè)級(jí)別有多少級(jí)別和多少次。
語法
gl(n, k, labels)
以下是所使用的參數(shù)的說明 -
-
n是給出級(jí)數(shù)的整數(shù)。
-
k是給出復(fù)制數(shù)目的整數(shù)。
-
labels是所得因子水平的標(biāo)簽向量。
例
v <- gl(3, 4, labels = c("Tampa", "Seattle","Boston"))
print(v)
當(dāng)我們執(zhí)行上面的代碼,它產(chǎn)生以下結(jié)果 -
Tampa Tampa Tampa Tampa Seattle Seattle Seattle Seattle Boston [10] Boston Boston Boston Levels: Tampa Seattle Boston
分享名稱:創(chuàng)新互聯(lián)R語言教程:R語言因子
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