[英]Recursive function sum of digits R
I try to write a recursive function that returns the sum of digits.我尝试编写一个返回数字总和的递归函数。 However, the program below doesn't seem to do the trick.
然而,下面的程序似乎并没有做到这一点。
getSum = function(i) {
if (i < 0) {Print("Please enter a positive number")}
if (i >= 0) {getSum(i - floor(i / 10) - i %% 10) + floor(i / 10) + i %% 10}
It gives two errors:它给出了两个错误:
Error: evaluation nested too deeply: infinite recursion / options(expressions=)?
Error during wrapup: evaluation nested too deeply: infinite recursion /
options(expressions=)?
What can I do to solve this?我能做些什么来解决这个问题?
Use this用这个
if (i >= 0)
{sum(sapply(strsplit(as.character(i),""),as.numeric))}
Of course this works for whole numbers.当然,这适用于整数。 If your need is greater more regex can be added to accommodate that
如果您的需求更大,可以添加更多正则表达式来适应
Edited!已编辑! Oops totally missed that you want a recursive function
哎呀完全错过了你想要一个递归函数
Do you want something like this?你想要这样的东西吗?
getSum = function(i){
i = abs(floor(i))
if (nchar(i) == 1){
return(i)
} else {
getSum(floor(i/10)) +i%%10 #Minorpt (suggested by @DashingQuark)
}
}
In R, it is recommended to use Recall
for creating a recursive function.在 R 中,建议使用
Recall
来创建递归函数。
I am using @db's function, but demonstrating with Recall
我正在使用@db 的函数,但使用
Recall
演示
getSum = function( i )
{
if (nchar(i) == 1){
return(i)
} else if (i < 0 ) {
"Please enter a positive number"
}else {
print(i)
Recall( i = floor(i/10)) +i%%10
}
}
getSum(0)
# [1] 0
getSum(1)
# [1] 1
getSum(-1)
# [1] "Please enter a positive number"
getSum(5)
# [1] 5
getSum(100)
# [1] 100
# [1] 10
# [1] 1
getSum( 23)
# [1] 23
# [1] 5
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