R:获得三个数字的所有组合加起来为100 [英] R: get all combinations of three numbers that add up to 100

问题描述

我有三个变量:X，Y和Z.我想找到X，Y和Z的所有组合加起来等于100.X，Y和Z只能取[0,100]之间的值.输出看起来应该像这样:

I have three variables: X, Y, and Z. I want to find all the combinations of X, Y and Z that add up to 100. X, Y and Z can only take values between [0,100]. The ouput should look somehtinkg like this:

  X   Y   Z   Sum
100   0   0   100
 99   1   0   100
 99   0   1   100
 98   2   0   100
 98   1   1   100
 98   0   2   100

以此类推...

关于如何获得所有可能组合的任何建议?

Any suggestion on how to get all the possible combinations?

推荐答案

由于只有三列限制为1:100，因此这很容易造成暴力.如果范围更大，将需要一个更聪明的解决方案.

Since you're limited to 1:100 on only three columns, this is easy to brute force. Would need a more clever solution if the range was larger.

library(data.table)

df <- expand.grid(X = 0:100,
                  Y = 0:100,
                  Z = 0:100)

setDT(df)

df[, Sum := X + Y + Z]
df[Sum == 100]
#         X Y   Z Sum
#    1: 100 0   0 100
#    2:  99 1   0 100
#    3:  98 2   0 100
#    4:  97 3   0 100
#    5:  96 4   0 100
#   ---              
# 5147:   1 1  98 100
# 5148:   0 2  98 100
# 5149:   1 0  99 100
# 5150:   0 1  99 100
# 5151:   0 0 100 100

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