Returns the first and last "parts" (rows or members) of a spectrum,
dataframe, vector, function, table or ftable. In other words, the combined
output from methods head and tail.
Usage
head_tail(x, n, ...)
# Default S3 method
head_tail(x, n = 3L, ...)
# S3 method for class 'data.frame'
head_tail(x, n = 3L, ...)
# S3 method for class 'matrix'
head_tail(x, n = 3L, ...)
# S3 method for class '`function`'
head_tail(x, n = 6L, ...)
# S3 method for class 'table'
head_tail(x, n = 6L, ...)
# S3 method for class 'ftable'
head_tail(x, n = 6L, ...)Value
An object (usually) like x but smaller, except when
n = 0. For ftable objects x, a transformed
format(x).
Details
The value returned by head_tail() is equivalent to row
binding the the values returned by head() and tail(),
although not implemented in this way. The same specializations as defined
in package 'utils' for head() and tail() have been
implemented.
Methods (by class)
head_tail(default):head_tail(data.frame):head_tail(matrix):head_tail(`function`):head_tail(table):head_tail(ftable):
Note
For some types of input, like functions, the output may be confusing,
however, we have opted for consistency with existing functions. The code is
in part a revision of that of head() and tail() from package
‘utils’. This method is especially useful when checking spectral
data, as both ends are of interest.
head_tail() methods for function, table and ftable classes, are
wrappers for head() method.
See also
head, and compare the examples and the values
returned to the examples below.
Examples
head_tail(1:20)
#> [1] 1 2 3 18 19 20
head_tail(1:20, 12)
#> [1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
head_tail(1:20, -7)
#> [1] 8 9 10 11 12 13
head_tail(1:20, -10)
#> integer(0)
head_tail(letters)
#> [1] "a" "b" "c" "x" "y" "z"
head_tail(sun.spct)
#> Object: source_spct [6 x 3]
#> Wavelength range 280-800 nm, step 0.9230769-516.1538 nm
#> Label: sunlight, simulated
#> Measured on 2010-06-22 09:51:00 UTC
#> Measured at 60.20911 N, 24.96474 E; Kumpula, Helsinki, FI
#> Variables:
#> w.length: Wavelength [nm]
#> s.e.irrad: Spectral energy irradiance [W m-2 nm-1]
#> s.q.irrad: Spectral photon irradiance [mol s-1 m-2 nm-1]
#> --
#> # A tibble: 6 × 3
#> w.length s.e.irrad s.q.irrad
#> <dbl> <dbl> <dbl>
#> 1 280 0 0
#> 2 281. 0 0
#> 3 282. 0 0
#> 4 798 0.424 0.00000283
#> 5 799 0.419 0.00000280
#> 6 800 0.407 0.00000272
head_tail(sun.spct, 6)
#> Object: source_spct [12 x 3]
#> Wavelength range 280-800 nm, step 0.9230769-510.3846 nm
#> Label: sunlight, simulated
#> Measured on 2010-06-22 09:51:00 UTC
#> Measured at 60.20911 N, 24.96474 E; Kumpula, Helsinki, FI
#> Variables:
#> w.length: Wavelength [nm]
#> s.e.irrad: Spectral energy irradiance [W m-2 nm-1]
#> s.q.irrad: Spectral photon irradiance [mol s-1 m-2 nm-1]
#> --
#> # A tibble: 12 × 3
#> w.length s.e.irrad s.q.irrad
#> <dbl> <dbl> <dbl>
#> 1 280 0 0
#> 2 281. 0 0
#> 3 282. 0 0
#> 4 283. 0 0
#> 5 284. 0 0
#> 6 285. 0 0
#> 7 795 0.415 0.00000276
#> 8 796 0.408 0.00000272
#> 9 797 0.414 0.00000276
#> 10 798 0.424 0.00000283
#> 11 799 0.419 0.00000280
#> 12 800 0.407 0.00000272
head_tail(sun.data)
#> w.length s.e.irrad s.q.irrad
#> 1 293 2.609665e-06 6.391823e-12
#> 2 294 6.142401e-06 1.509586e-11
#> 3 295 2.176175e-05 5.366463e-11
#> 506 798 4.236281e-01 2.825921e-06
#> 507 799 4.185850e-01 2.795778e-06
#> 508 800 4.069055e-01 2.721171e-06
head_tail(as.matrix(sun.data))
#> w.length s.e.irrad s.q.irrad
#> [1,] 293 2.609665e-06 6.391823e-12
#> [2,] 294 6.142401e-06 1.509586e-11
#> [3,] 295 2.176175e-05 5.366463e-11
#> [4,] 798 4.236281e-01 2.825921e-06
#> [5,] 799 4.185850e-01 2.795778e-06
#> [6,] 800 4.069055e-01 2.721171e-06
head_tail(sun_evening.spct)
#> Object: source_spct [6 x 3]
#> containing 2 spectra in long form
#> Wavelength range 290-1000 nm, step 0.34-708.38 nm
#> Label: cosine.hour.9
#> time.01 measured on 2023-06-12 18:38:00.379657 UTC
#> time.05 measured on 2023-06-12 18:42:00.769065 UTC
#> Measured at 60.227 N, 24.018 E; Viikki, Helsinki, FI
#> Variables:
#> w.length: Wavelength [nm]
#> s.e.irrad: Spectral energy irradiance [W m-2 nm-1]
#> --
#> # A tibble: 6 × 3
#> w.length s.e.irrad spct.idx
#> <dbl> <dbl> <fct>
#> 1 290 0 time.01
#> 2 290. 0 time.01
#> 3 291. 0 time.01
#> 4 999. 0.0328 time.05
#> 5 1000. 0.0324 time.05
#> 6 1000. 0.0322 time.05
head_tail(sun_evening.mspct, 1L)
#> Object: source_mspct [2 x 1]
#> --- Member: time.01 ---
#> Object: source_spct [1,593 x 2]
#> Wavelength range 290-1000 nm, step 0.34-0.47 nm
#> Label: cosine.hour.9
#> Measured on 2023-06-12 18:38:00.379657 UTC
#> Measured at 60.227 N, 24.018 E; Viikki, Helsinki, FI
#> Variables:
#> w.length: Wavelength [nm]
#> s.e.irrad: Spectral energy irradiance [W m-2 nm-1]
#> --
#> # A tibble: 1,593 × 2
#> w.length s.e.irrad
#> <dbl> <dbl>
#> 1 290 0
#> 2 290. 0
#> 3 291. 0
#> 4 291. 0
#> 5 292. 0
#> 6 292. 0
#> 7 293. 0
#> 8 293. 0
#> 9 294. 0
#> 10 294. 0
#> # ℹ 1,583 more rows
#> --- Member: time.05 ---
#> Object: source_spct [1,593 x 2]
#> Wavelength range 290-1000 nm, step 0.34-0.47 nm
#> Label: cosine.hour.9
#> Measured on 2023-06-12 18:42:00.769065 UTC
#> Measured at 60.227 N, 24.018 E; Viikki, Helsinki, FI
#> Variables:
#> w.length: Wavelength [nm]
#> s.e.irrad: Spectral energy irradiance [W m-2 nm-1]
#> --
#> # A tibble: 1,593 × 2
#> w.length s.e.irrad
#> <dbl> <dbl>
#> 1 290 0
#> 2 290. 0
#> 3 291. 0
#> 4 291. 0
#> 5 292. 0
#> 6 292. 0
#> 7 293. 0
#> 8 293. 0
#> 9 294. 0
#> 10 294. 0
#> # ℹ 1,583 more rows
#>
#> --- END ---