How to avoid showing headers in STOUT of R data.table?

Question

I am trying to avoid showing headers in R's STOUT of data.table output. Akrun says in the related thread the the null route may be possible with print.

If you are not okay with the NULL route, then you may have to create a custom function for print by modifying the existing print

Code

library(data.table)

# http://stackoverflow.com/a/43706344/54964

DF[time < 8]

Output where I want to avoid the first header line in STOUT

#    Field time  T Experiment time_expected    timeN
# 1: Acute  0.0  0          A             6 0.000000

akrun · Accepted Answer · 2017-05-01T05:36:12.043

We can use the unname

unname(DF[time <8])[]

# 1: Acute 0.0  0 A 6 0.000000
# 2:    An 7.7 26 B 6 1.283333
# 3:    Fo 0.0  0 B 5 0.000000
# 4: Acute 7.5  1 C 6 1.250000
# 5:    An 7.9 43 C 6 1.316667
# 6:    En 0.0  0 C 6 0.000000
# 7:    Fo 5.4  1 C 5 1.080000
# 8:    An 7.8 77 D 6 1.300000
# 9:    En 0.0  0 D 6 0.000000
#10:    Fo 0.0  0 D 5 0.000000
#11: Acute 0.0  0 E 6 0.000000
#12:    An 7.9 60 E 6 1.316667
#13:    Fo 0.0  0 E 5 0.000000
#14:    Fo 7.9  3 F 5 1.580000

One option to avoid the empty line would be

cat(trimws(capture.output(unname(DF[time <8]))[-1]) , sep="\n")
#1: Acute 0.0  0 A 6 0.000000
#2:    An 7.7 26 B 6 1.283333
#3:    Fo 0.0  0 B 5 0.000000
#4: Acute 7.5  1 C 6 1.250000
#5:    An 7.9 43 C 6 1.316667
#6:    En 0.0  0 C 6 0.000000
#7:    Fo 5.4  1 C 5 1.080000
#8:    An 7.8 77 D 6 1.300000
#9:    En 0.0  0 D 6 0.000000
#10:    Fo 0.0  0 D 5 0.000000
#11: Acute 0.0  0 E 6 0.000000
#12:    An 7.9 60 E 6 1.316667
#13:    Fo 0.0  0 E 5 0.000000
#14:    Fo 7.9  3 F 5 1.580000

For better formatting, the trimws could be avoided

cat(capture.output(unname(DF[time <8]))[-1] , sep="\n")
# 1: Acute 0.0  0 A 6 0.000000
# 2:    An 7.7 26 B 6 1.283333
# 3:    Fo 0.0  0 B 5 0.000000
# 4: Acute 7.5  1 C 6 1.250000
# 5:    An 7.9 43 C 6 1.316667
# 6:    En 0.0  0 C 6 0.000000
# 7:    Fo 5.4  1 C 5 1.080000
# 8:    An 7.8 77 D 6 1.300000
# 9:    En 0.0  0 D 6 0.000000
#10:    Fo 0.0  0 D 5 0.000000
#11: Acute 0.0  0 E 6 0.000000
#12:    An 7.9 60 E 6 1.316667
#13:    Fo 0.0  0 E 5 0.000000
#14:    Fo 7.9  3 F 5 1.580000

How can you avoid the newline there? Assume you print one line before the data that you would like to be together with the data. Etc `field <- "Orto"; sprintf("%s ", field);`. — Léo Léopold Hertz 준영, May 01 '17 at 05:31
@LéoLéopoldHertz준영 Did you meant to have `trimws(capture.output(unname(DF[time <8]))[-1])` — akrun, May 01 '17 at 05:34
I expanded another similar case here about the presentation of like Vim's `tabstop` http://stackoverflow.com/q/43715031/54964 — Léo Léopold Hertz 준영, May 01 '17 at 06:09

How to avoid showing headers in STOUT of R data.table?

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