R's default head or tail functions print 6 or so rows and all columns. When you have a dataset that has a rather large number of columns, printing can be very poor, spilling over several rows.
The default output would look like
> dim(xy)
[1] 43 205
> head(xy)
Sample SLC25A5 MEOX1 CD4 HFE GABRA3 RNH1 VIM MYOC
1 sample 1 169.28930 0.08670971 18.975543 14.149516 0.10174355 5.021980 1674.99418 0.2268739
2 sample 2 122.55490 0.11898911 16.644021 5.116629 0.06980979 4.246349 610.15708 0.9339964
3 sample 3 13.49505 0.39190042 7.006248 8.686389 0.61902692 1.242957 88.91675 11.1807812
4 sample 4 111.84583 0.07831660 8.329725 2.129984 0.34920184 8.478207 194.47382 0.0000000
CAPG ZIC2 EPHA3 ELN NTN1 ABCC9 CYBRD1 NTN4 NUAK1 SLC25A3
1 48.951242 0.9216751 5.97980198 3.591096 4.5935819 12.916405 45.980617 10.402553 6.992939 81.73932
2 10.396297 1.0434491 19.52954610 4.078562 5.2744688 40.005469 17.813941 15.819005 9.638139 60.31633
3 2.468217 3.6529801 2.96681949 5.578765 0.5051865 6.682470 1.563846 1.976812 2.269706 11.34410
4 24.162310 3.4463885 0.07879854 3.225239 2.1506768 1.343375 20.593887 4.886979 3.763131 56.44569
...
spilling columns over several lines with no end in sight for data with large number of colums (think expressions in bioinformatics).
It came down to typing xy[1:5, 1:5] for the rest of my life or develop a function that would make this easier. Enter peep. It prints a few first and last rows and columns. If any columns or rows have been omitted, it adds a horizontal or vertical delimiter of dots to indicate that there's something there.
> peep(xy)
Sample SLC25A5 MEOX1 CD4 HFE GABRA3 MMP12 SPON1 MSMB CCL4 CCL3
01: sample 1 169.3 0.08671 18.98 14.15 0.1017 · 5.77 45.49 8.803 77.19 76.08
02: sample 2 122.6 0.119 16.64 5.117 0.06981 · 114.9 274.7 0.2449 44.92 41.04
03: sample 3 13.5 0.3919 7.006 8.686 0.619 · 4.861 2.803 278 9.299 5.599
04: sample 4 111.8 0.07832 8.33 2.13 0.3492 · 146.8 560.5 0 25.22 16.66
05: sample 5 92.04 0 0.9135 0.8531 0.8672 · 91.63 8.617 4.848 8.899 6.03
06: sample 6 63.44 0.3779 4.487 11.16 4.573 · 273.6 7.65 20.03 15.84 9.727
· · · · · · · · · · · ·
38: sample 38 119.9 0.06032 2.194 8.856 0 · 1.158 4.308 0 8.464 19.14
39: sample 39 83.36 0 5.265 1.505 0 · 7.512 225.4 0 17.25 16.83
40: sample 40 100.1 0 4.783 1.692 0 · 88.81 18.54 0 55.66 5.438
41: sample 41 77.02 0.01632 14.92 3.389 0.01915 · 0 68.71 0 18.79 11.5
42: sample 42 39.37 0.1706 4.553 4.284 0.2891 · 6.476 20.21 8.893 21.19 9.978
43: sample 43 36.44 0 1.064 4.322 0.4157 · 0.544 5.627 0 5.444 2.933
This works has been inspired by data.table and pandas, a package for working with DataFrames in Python.
To install from GitHub, try using package remotes
remotes::install_github("romunov/peep")