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使用冒號(hào)運(yùn)算帶有數(shù)值數(shù)據(jù)（數(shù)值的增加為1） # Creating a sequence from 5 to 13. v <- 5:13 print(v) # Creating a sequence from 6.6 to 12.6. v <- 6.6:12.6 print(v) # If the final element specified does not belong to the sequence then it is discarded. v <- 3.8:11.4 print(v) 當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] 5 6 7 8 9 10 11 12 13 [1] 6.6 7.6 8.6 9.6 10.6 11.6 12.6 [1] 3.8 4.8 5.8 6.8 7.8 8.8 9.8 10.8 使用序列 (Seq.) 運(yùn)算符 # Create vector with elements from 5 to 9 incrementing by 0.4. print(seq(5, 9, by=0.4)) 當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8 8.2 8.6 9.0 charToRaw：把字符串轉(zhuǎn)化為數(shù)字?jǐn)?shù)組進(jìn)行輸出。 使用 c() 函數(shù) 非字符值強(qiáng)制轉(zhuǎn)換為字符類型，如果該元素之一是字符。 # The logical and numeric values are converted to characters.
s <- c('apple','red',5,TRUE)
print(s)
當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] "apple" "red" "5" "TRUE" 訪問向量元素一個(gè)向量的元素使用索引訪問。[]括號(hào)是用來進(jìn)行索引。索引位置始于1。 給出索引負(fù)值將從結(jié)果元素中丟棄。TRUE, FALSE 或 0 和 1。也可用于索引。 # Accessing vector elements using position.
t <- c("Sun","Mon","Tue","Wed","Thurs","Fri","Sat")
u <- t[c(2,3,6)]//訪問2，3，6位置的元素
print(u)
# Accessing vector elements using logical indexing.
v <- t[c(TRUE,FALSE,FALSE,FALSE,FALSE,TRUE,FALSE)]//凡是false的位置，結(jié)果不做輸出
print(v)
# Accessing vector elements using negative indexing.
x <- t[c(-2,-5)]//2和5索引位置數(shù)據(jù)由于是負(fù)數(shù)，表示不輸出
print(x)
# Accessing vector elements using 0/1 indexing.
y <- t[c(0,0,0,0,0,0,1)] //如果是數(shù)組相等的位置，0位置表示數(shù)值不做輸出。
print(y)
當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] "Mon" "Tue" "Fri" [1] "Sun" "Fri" [1] "Sun" "Tue" "Wed" "Fri" "Sat" [1] "Sun" 向量操作向量運(yùn)算相同長度的兩個(gè)矢量可以加，減，乘或除給出的結(jié)果為向量輸出。 # Create two vectors. v1 <- c(3,8,4,5,0,11) v2 <- c(4,11,0,8,1,2) # Vector addition. add.result <- v1+v2 print(add.result) # Vector substraction. sub.result <- v1-v2 print(sub.result) # Vector multiplication. multi.result <- v1*v2 print(multi.result) # Vector division. divi.result <- v1/v2 print(divi.result) 當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] 7 19 4 13 1 13 [1] -1 -3 4 -3 -1 9 [1] 12 88 0 40 0 22 [1] 0.7500000 0.7272727 Inf 0.6250000 0.0000000 5.5000000 向量元素回收利用如果我們算術(shù)運(yùn)算不等長的兩個(gè)向量，那么短的向量的元素被循環(huán)以完成操作。 v1 <- c(3,8,4,5,0,11) v2 <- c(4,11) # V2 becomes c(4,11,4,11,4,11) add.result <- v1+v2 print(add.result) sub.result <- v1-v2 print(sub.result) 當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] 7 19 8 16 4 22 [1] -1 -3 0 -6 -4 0 向量元素排序一個(gè)向量中元素可以使用 sort()函數(shù)進(jìn)行排序。 v <- c(3,8,4,5,0,11, -9, 304)
# Sort the elements of the vector.
sort.result <- sort(v)
print(sort.result)
# Sort the elements in the reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)
# Sorting character vectors.
v <- c("Red","Blue","yellow","violet")//按照首字母進(jìn)行排序
sort.result <- sort(v)
print(sort.result)
# Sorting character vectors in reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)
當(dāng)我們上面的代碼執(zhí)行時(shí)，它產(chǎn)生以下結(jié)果： [1] -9 0 3 4 5 8 11 304 [1] 304 11 8 5 4 3 0 -9 [1] "Blue" "Red" "violet" "yellow" [1] "yellow" "violet" "Red" "Blue"
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