2.19 study

기초 명령어 실습.R

@@ -34,3 +34,121 @@ table(is.na(xx1))
 
 x1 = c(1,'love',TRUE,2+3i)
 x1
+
+v1 = c(27,35,47,41)
+mode(v1)
+is.numeric(v1)
+is.na(v1)
+table(is.na(v1))
+
+v2 = c(27,35,47,NA,55)
+mode(v2)
+is.numeric(v2)
+is.na(v2)
+table(is.na(v2))
+
+length(v1)
+length(v2)
+
+names(v1)
+names(v1) = c('kim','lee','park','choi')
+
+names(v1)
+
+## Indexing ## 대괄호 == [ ] => 추출해라
+
+v1
+v1[1]
+v1[1:3]
+v1[-4]
+v1[c(2,4)]
+
+v1 = 1:3
+v2 = 4:6
+v3 = v1+v2 # can add list
+
+v1 = 1:3
+v2 = 1:6
+v3 = v1+v2 # reusable add
+v3
+
+### 데이터거래사
+
+## Factor, ordered Factor (등급을 정할 수 있는)
+
+gender = c('m','f','f','m','f','f')
+gender_factor = factor(gender)
+
+levels(gender_factor)
+
+gender_factor2 = factor(gender, levels = c('m','f'), labels = c('남자','여자'))
+gender_factor2
+
+gender_factor3 = factor(gender,ordered = TRUE)
+gender_factor3
+
+
+## Matrix ##
+v1 = 1:3
+v2 = 4:6
+m1 = rbind(v1,v2)
+m2 = cbind(v1,v2)
+v1
+v2
+m1
+m2
+
+m1[2,1] == 8
+m1[2,1] = 8
+m1[,3]
+
+is.na(m1)
+table(is.na(m1))
+
+m1[1,1] = NA
+m1[2,3] = NA
+
+table(is.na(m1))
+str(m1)
+
+m3 = matrix(1:4, nrow = 2, ncol = 2)
+m4 = matrix(1:4, nrow = 2, ncol = 2, byrow = TRUE)
+m3
+m4[2,1] = NA
+
+
+## array ##
+a1 = array(1:10, dim=10)
+a2 = array(1:10, dim=c(2, 5))
+a3 = array(1:10, dim=c(3, 3, 4))
+
+a1
+a2
+a3[,,2][3,3] = 100
+a3
+
+## DataFrame ##
+id = 1:5
+age = c(29, 32, 47, 35, 23)
+gender = c('f','m','m','f','f')
+height = c(163, 177, 172, 157, 169)
+DF1 = data.frame(id, age, gender, height)
+DF2 = data.frame(id, age, gender, height, stringsAsFactors=FALSE)
+DF3 = data.frame(id, age, gender, height, stringsAsFactors=TRUE)
+DF1
+DF2
+DF3
+
+View(DF3)
+str(DF3)
+
+DF4 = DF3[-1]
+DF4
+
+View(DF4)
+str(DF4)
+
+## 기술통계량 ##
+library('psych')
+
+describe(DF4)