<p><div><div><div><div data-width="100" data-show-faces="false" data-send="true" data-layout="button_count" data-height="21" data-href="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/"></div></div><div><a data-url="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/" data-counturl="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/" data-count="horizontal" data-text="Fastest Way to Add New Variables to A Large Data.Frame" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
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(This article was first published on <strong><a href="https://statcompute.wordpress.com/2016/10/31/fastest-way-to-add-new-variables-to-a-large-data-frame/"> S+/R – Yet Another Blog in Statistical Computing</a></strong>, and kindly contributed to <a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers)</a> </div>
<pre>
pkgs &lt;- list(&quot;hflights&quot;, &quot;doParallel&quot;, &quot;foreach&quot;, &quot;dplyr&quot;, &quot;rbenchmark&quot;, &quot;data.table&quot;)
lapply(pkgs, require, character.only = T)

data(hflights)

benchmark(replications = 10, order = &quot;user.self&quot;, relative = &quot;user.self&quot;,
  transform = {
    ### THE GENERIC FUNCTION MODIFYING THE DATA.FRAME, SIMILAR TO DATA.FRAME() ###
    transform(hflights, wday = ifelse(DayOfWeek %in% c(6, 7), 'weekend', 'weekday'), delay = ArrDelay + DepDelay)
  },
  within    = {
    ### EVALUATE THE EXPRESSION WITHIN THE LOCAL ENVIRONMENT ###
    within(hflights, {wday = ifelse(DayOfWeek %in% c(6, 7), 'weekend', 'weekday'); delay = ArrDelay + DepDelay})
  },
  mutate   = {
    ### THE SPECIFIC FUNCTION IN DPLYR PACKAGE TO ADD VARIABLES ###
    mutate(hflights, wday = ifelse(DayOfWeek %in% c(6, 7), 'weekend', 'weekday'), delay = ArrDelay + DepDelay)
  },
  foreach = {
    ### SPLIT AND THEN COMBINE IN PARALLEL ###
    registerDoParallel(cores = 2)
    v &lt;- c(names(hflights), 'wday', 'delay')
    f &lt;- expression(ifelse(hflights$DayOfWeek %in% c(6, 7), 'weekend', 'weekday'),
                    hflights$ArrDelay + hflights$DepDelay)
    df &lt;- foreach(fn = iter(f), .combine = mutate, .init = hflights) %dopar% {
      eval(fn)
    }
    names(df) &lt;- v
  },
  data.table = {
    ### DATA.TABLE ###
    data.table(hflights)[, c(&quot;wday&quot;, &quot;delay&quot;) := list(ifelse(hflights$DayOfWeek %in% c(6, 7), 'weekend', 'weekday'), hflights$ArrDelay + hflights$DepDelay)]
  }
)

#         test replications elapsed relative user.self sys.self user.child
# 4    foreach           10   1.442    1.000     0.240    0.144      0.848
# 2     within           10   0.667    2.783     0.668    0.000      0.000
# 3     mutate           10   0.679    2.833     0.680    0.000      0.000
# 5 data.table           10   0.955    3.983     0.956    0.000      0.000
# 1  transform           10   1.732    7.200     1.728    0.000      0.000
</pre>
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<p><div><div><div><div data-width="55" data-show-faces="false" data-send="true" data-layout="box_count" data-height="62" data-href="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/"></div></div><div><a data-url="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/" data-counturl="https://www.r-bloggers.com/fastest-way-to-add-new-variables-to-a-large-data-frame/" data-count="vertical" data-text="Fastest Way to Add New Variables to A Large Data.Frame" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
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