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# 在两点之间缩放系列

2019-09-24 16:36:21

# generate series from exponential distr

s = sort(rexp(100))

# scale/interpolate 's' such that it starts at 0 and ends at 1?

# approx(s)

# scale(s)

## 3 回答

s = sort(rexp(100))

range01 <- function(x){(x-min(x))/(max(x)-min(x))}

range01(s)

[1] 0.000000000 0.003338782 0.007572326 0.012192201 0.016055006 0.017161145

[7] 0.019949532 0.023839810 0.024421602 0.027197168 0.029889484 0.033039408

[13] 0.033783376 0.038051265 0.045183382 0.049560233 0.056941611 0.057552543

[19] 0.062674982 0.066001242 0.066420884 0.067689067 0.069247825 0.069432174

[25] 0.070136067 0.076340460 0.078709590 0.080393512 0.085591881 0.087540132

[31] 0.090517295 0.091026499 0.091251213 0.099218526 0.103236344 0.105724733

[37] 0.107495340 0.113332392 0.116103438 0.124050331 0.125596034 0.126599323

[43] 0.127154661 0.133392300 0.134258532 0.138253452 0.141933433 0.146748798

[49] 0.147490227 0.149960293 0.153126478 0.154275371 0.167701855 0.170160948

[55] 0.180313542 0.181834891 0.182554291 0.189188137 0.193807559 0.195903010

[61] 0.208902645 0.211308713 0.232942314 0.236135220 0.251950116 0.260816843

[67] 0.284090255 0.284150541 0.288498370 0.295515143 0.299408623 0.301264703

[73] 0.306817872 0.307853369 0.324882091 0.353241217 0.366800517 0.389474449

[79] 0.398838576 0.404266315 0.408936260 0.409198619 0.415165553 0.433960390

[85] 0.440690262 0.458692639 0.464027428 0.474214070 0.517224262 0.538532221

[91] 0.544911543 0.559945121 0.585390414 0.647030109 0.694095422 0.708385079

[97] 0.736486707 0.787250428 0.870874773 1.000000000

library("scales")

rescale(s)

rescale(s, to=c(0,10))

rescale(s, from=c(0, max(s)))

reshape::rescaler.default(s, type = "range")

> system.time(replicate(100, range01(s)))

user  system elapsed

0.56    0.12    0.69

> system.time(replicate(100, reshape::rescaler.default(s, type = "range")))

user  system elapsed

0.53    0.18    0.70

range02 <- function(x) {

(x - min(x, na.rm=TRUE)) / diff(range(x, na.rm=TRUE))

}

> system.time(replicate(100, range02(s)))

user  system elapsed

0.56    0.12    0.68

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