R語言中因子相關(guān)知識點詳解
因子是用于對數(shù)據(jù)進行分類并將其存儲為級別的數(shù)據(jù)對象。 它們可以存儲字符串和整數(shù)。 它們在具有有限數(shù)量的唯一值的列中很有用。 像“男性”,“女性”和True,F(xiàn)alse等。它們在統(tǒng)計建模的數(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,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)
當我們執(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
更改級別順序
可以通過使用新的等級次序再次應用因子函數(shù)來改變因子中的等級的順序。
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
生成因子級別
我們可以使用gl()函數(shù)生成因子級別。 它需要兩個整數(shù)作為輸入,指示每個級別有多少級別和多少次。
語法
gl(n, k, labels)
以下是所使用的參數(shù)的說明 -
- n是給出級數(shù)的整數(shù)。
- k是給出復制數(shù)目的整數(shù)。
- labels是所得因子水平的標簽向量。
例
v <- gl(3, 4, labels = c("Tampa", "Seattle","Boston"))
print(v)
當我們執(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
以上就是R語言中因子相關(guān)知識點詳解的詳細內(nèi)容,更多關(guān)于R語言因子的資料請關(guān)注腳本之家其它相關(guān)文章!
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