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Kan, Hao-ChengLunghwa University of Science and Technology
http://kanchengzxdfgcv.blogspot.tw/
> as.numeric(TRUE)> as.numeric(FALSE)> as.character(TRUE)> as.character(FALSE)> as.factor(TRUE)> as.factor(FALSE)>> k = "kan"> class(k)> as.character(k)>> n = 123> class(n)> as.numeric(n)>> test = as.numeric(k)> test
> 1 == 1> 1 < 1> 1 <= 1> 1 > 1> 1 >= 1> 1 != 1> toCheck = 1
if (toCheck == 1){
print("hello")}
if (toCheck == 0){
print("hello")}
check.bool = function(x){if (x == 1){
print("hello")}else{
print("goodbye")}
}
> check.bool(1)> check.bool(0)> check.bool("k")> check.bool(TRUE)
check.bool = function(x){if (x == 1){
print("hello")} else if (x == 0){
print("goodbye")} else{
print("confused")}
}
> check.bool(1)> check.bool(0)> check.bool(2)> check.bool("k")
use.switch = function(x){switch(x,"a"="first","b"="second","z"="last","c"="third","other")
}
> use.switch("a")> use.switch("b")> use.switch("c")> use.switch("d")> use.switch("OwO")> use.switch("z")> use.switch(1)> use.switch(2)> use.switch(3)> use.switch(4)> use.switch(5)> use.switch(6)> is.null(use.switch(6))
> ifelse(1 == 1, "Yes", "No")> ifelse(1 == 0, "Yes", "No")>> toTest = c(1, 1, 0, 1, 0, 1)> class(toTest)> toTest>> ifelse(toTest == 1, "Yes", "No")> ifelse(toTest == 1, toTest * 3, toTest)> ifelse(toTest == 1, toTest * 3, "Zero")>> toTest[2] = NA> class(toTest)> toTest>> ifelse(toTest == 1, "Yes", "No")> ifelse(toTest == 1, toTest * 3, toTest)> ifelse(toTest == 1, toTest * 3, "Zero")
> a = c(1, 1, 0, 1)> b = c(2, 1, 0, 1)> bs = c(2, 1, 0, 1)>> ifelse(a == 1 & b == 1, "Yes", "No")> ifelse(a == 1 && b == 1, "Yes", "No")> ifelse(a == 1 && bs == 1, "Yes", "No")
ifelse(a == 1 & b == 1, "Yes", "No") ifelse(a == 1 && b == 1, "Yes", "No")
squfc = function(xsqu,ysqu){if( xsqu <= 0 || ysqu <= 0|| is.na(xsqu) || is.na( ysqu) || is.character(xsqu) ||is.character(ysqu)){
print(NA)}else{
squmatem = xsqu * ysqureturn(squmatem)
}}
> squfc( 3, 4)> squfc( 0, 4)> squfc( 3, 0)> squfc( 3, NA)> squfc( NA, 4)> squfc( 3, "Hi")> squfc( "Hi", 4)>> ww = c(1,NA,3,4,5)> qq = c(6,7,NA,9,10)> squfc(ww,qq)