[英]Create matrix of features using regex?
假設我有一個101個變量的數據框。 我選擇一個所謂的Y作為因變量,其余100個所謂的x_1,X_2,...,X_ {100}作為自變量。
現在,我想創建一個包含100個獨立變量的矩陣。 有哪些直接方法? 就像我建立線性回歸模型時一樣,只需使用“。” 作為正則表達式,即lm(Y ~ ., _____)
您可以使用grep
函數提取與數據框的獨立變量關聯的列名稱。 然后,您可以將其轉換為矩陣。 請參見下面的代碼:
# simulation of the data frame with 100 measurements and 101 variables
n <- 100
df <- data.frame(matrix(1:101 * n, ncol = 101))
names(df) <- c(paste0("X_", 1:100), "Y")
# extract matrix of Xs
m_x <- as.matrix(df[, grep("^X", names(df))])
dimnames(m_x)
輸出:
[[1]]
NULL
[[2]]
[1] "X_1" "X_2" "X_3" "X_4" "X_5" "X_6" "X_7" "X_8" "X_9" "X_10" "X_11" "X_12" "X_13" "X_14" "X_15"
[16] "X_16" "X_17" "X_18" "X_19" "X_20" "X_21" "X_22" "X_23" "X_24" "X_25" "X_26" "X_27" "X_28" "X_29" "X_30"
[31] "X_31" "X_32" "X_33" "X_34" "X_35" "X_36" "X_37" "X_38" "X_39" "X_40" "X_41" "X_42" "X_43" "X_44" "X_45"
[46] "X_46" "X_47" "X_48" "X_49" "X_50" "X_51" "X_52" "X_53" "X_54" "X_55" "X_56" "X_57" "X_58" "X_59" "X_60"
[61] "X_61" "X_62" "X_63" "X_64" "X_65" "X_66" "X_67" "X_68" "X_69" "X_70" "X_71" "X_72" "X_73" "X_74" "X_75"
[76] "X_76" "X_77" "X_78" "X_79" "X_80" "X_81" "X_82" "X_83" "X_84" "X_85" "X_86" "X_87" "X_88" "X_89" "X_90"
[91] "X_91" "X_92" "X_93" "X_94" "X_95" "X_96" "X_97" "X_98" "X_99" "X_100"
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