将字符串转换为一位数字并求和 [英] Convert string to single digits and sum
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问题描述
我已经尝试了好几个小时来找到解决方案,但我失败了。
I've tried for hours to find a solution to what I thought was an easy task but I failed.
我有一个字符串,包含3个不同的字符('I','R'&'O')
,长度从1到6。
Eg
I have a string consisting of 3 different characters ('I','R' & 'O')
with length from 1 to 6.
E.g
IRRROO
RRORRR
IIR
RIRRO
每个字符代表一个数字 I = 1,R = 2,O = 3
我需要将此字符串转换为一个数字,再乘以位置并求和。例如
Each character represents a number I=1,R=2,O=3
I need to convert this string to a single number, multiply with position and sum the result. E.g
IRRROO ---> (1*1)+(2*2)+(2*3)+(2*4)+(3*5)+(3*6) =52
IIR ---> (1*1)+(1*2)+(2*3) =9
感谢
推荐答案
因子具有数值等效项。您可以在此示例中很好地利用它:
factors have numeric equivalents. You can leverage that nicely for this example:
# original
x1 <- "IRRROO"
# 1 2 3
levs <- c("I", "R", "O")
# split the string and convert to factors, then to numeric
x1f <- as.numeric(factor(strsplit(x1, "")[[1]], levels=levs))
# tally it up
sum(x1f * seq_along(x1f))
或作为一个不错的单行函数:
Or as a nice, single-line function:
sumValue <- function(x, levs=c("I", "R", "O"))
sum(seq.int(nchar(x)) * as.numeric(factor(strsplit(x, "")[[1]], levels=levs)))
sumValue("IRRROO")
# [1] 52
sumValue("IIR")
# [1] 9
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