抑制打印输出 sf 对象
suppress print output sf object
我正在尝试将 sf 对象的 head 等价物保存在列表中。当您在 sf class 上使用 head 时，它会向控制台打印有关数据周长的轻微误导信息，请参阅 bbox 信息与原始信息不同：
library(sf)
library(tidyverse)
nc <- st_read(system.file("shape/nc.shp", package = "sf"))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
head(nc)
# Simple feature collection with 6 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -81.74107 ymin: 36.07282 xmax: -75.77316 ymax: 36.58965
# geographic CRS: NAD27
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
那是因为我认为它为前 6 个观察而不是整个数据帧计算 bbox。作为替代方案，您可以 运行 以下 print （请参阅 bbox 与完整数据集相同）：
print(nc, n = getOption("sf_max_print", default = 6))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
# First 6 features:
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
如何在不将其打印到控制台的情况下将此打印对象保存在列表中（稍后将在函数中使用）？
当我粗略地把它放在一个列表中而不试图抑制它按预期打印的输出时：
a <- lst(dim(nc), head_sf = print(nc, n = getOption("sf_max_print", default = 6)))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
# First 6 features:
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
我以为 invisible 或 sink 会抑制输出，但我想不通，none 这些工作：
a <- invisible(lst(dim(nc), head_sf = print(nc, n = getOption("sf_max_print", default = 6))))
a <- lst(dim(nc), head_sf = invisible(print(nc, n = getOption("sf_max_print", default = 6))))
a <- lst(dim(nc), invisible(head_sf = print(nc, n = getOption("sf_max_print", default = 6))))
有什么建议吗？谢谢
编辑：
使用 invisible 和 capture.output 几乎可以得到我想要的（当我最初发布这个时输出不正确 - 我的错误）
a <- lst(dim(nc), invisible(capture.output(head_sf = print(nc, n = getOption("sf_max_print", default = 6)))))
a
$`dim(nc)`
[1] 100 15
$`invisible(...)`
[1] "Simple feature collection with 100 features and 14 fields"
[2] "geometry type: MULTIPOLYGON"
[3] "dimension: XY"
[4] "bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965"
[5] "geographic CRS: NAD27"
[6] "First 6 features:"
[7] " AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry"
[8] "1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3..."
[9] "2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3..."
[10] "3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3..."
[11] "4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3..."
[12] "5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3..."
[13] "6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3..."
可能是一个糟糕的方法，不知道 return 值将受到什么进一步处理（我觉得单独的暗淡，head_sf 是不可取的），如果你厌恶的话尤其糟糕循环，但使用 invisible(capture.output 的变体 :
library(sf)
library(tidyverse)
nc <- st_read(system.file("shape/nc.shp", package = "sf"))
nc1 <- nc
nc2 <- nc
nc3 <- nc
nc_lst <- list(nc1, nc2, nc3)
prepare_sf_head_for_further_process_loop3 <- function(nc_lst) {
a_quote <- list()
for(i in 1:length(nc_lst)) {
invisible(capture.output(a_quote[[i]] <- list(dims = dim(nc_lst[[i]]), head_sf = print(nc_lst[[i]], n = getOption('sf_max_print', default = 6)))))
}
return(a_quote)
}
>b3 <- prepare_sf_head_for_further_process_loop3(nc_lst)
>b3
[[1]]
[[1]]$dims
[1] 100 15
[[1]]$head_sf
Simple feature collection with 100 features and 14 fields
geometry type: MULTIPOLYGON
dimension: XY
bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
geographic CRS: NAD27
First 10 features:
AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74
1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1
2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0
3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5
4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1
5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9
6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7
7 0.062 1.547 1834 1834 Camden 37029 37029 15 286 0
8 0.091 1.284 1835 1835 Gates 37073 37073 37 420 0
9 0.118 1.421 1836 1836 Warren 37185 37185 93 968 4
10 0.124 1.428 1837 1837 Stokes 37169 37169 85 1612 1
NWBIR74 BIR79 SID79 NWBIR79 geometry
1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
2 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
3 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
4 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
5 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
6 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
7 115 350 2 139 MULTIPOLYGON (((-76.00897 3...
8 254 594 2 371 MULTIPOLYGON (((-76.56251 3...
9 748 1190 2 844 MULTIPOLYGON (((-78.30876 3...
10 160 2038 5 176 MULTIPOLYGON (((-80.02567 3...
>class(nc_lst[[1]]
[1] "sf" "data.frame"
>class(b3[[1]]$head_sf)
[1] "sf" "data.frame"
该死，不知道为什么 getOption('sf_max_print', default = 6) 没有限制为 6。
dplyer控制了quote/unquote，但我还没有研究出对此的应用。到目前为止，这些是我的错误建议。
另外，从 tidyverse What Hadley suggests，拿下 Hadley 并交换头部和打印，
glimpse_head2 <- function(x, n = 6) {
head(print(x, n))
invisible(x)
}
虽然这并没有变暗，但似乎比我上面的要简单得多，并且提供了所需的 bbox 值。并且仍然不限制为 6，因为 sfg 的 head 方法被硬编码为 10L:
> getS3method('head', 'sfg')
function (x, n = 10L, ...)
{
structure(head(unclass(x), n = n, ...), class = class(x))
}
<bytecode: 0x5646a6a38228>
<environment: namespace:sf>
我正在尝试将 sf 对象的 head 等价物保存在列表中。当您在 sf class 上使用 head 时，它会向控制台打印有关数据周长的轻微误导信息，请参阅 bbox 信息与原始信息不同：
library(sf)
library(tidyverse)
nc <- st_read(system.file("shape/nc.shp", package = "sf"))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
head(nc)
# Simple feature collection with 6 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -81.74107 ymin: 36.07282 xmax: -75.77316 ymax: 36.58965
# geographic CRS: NAD27
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
那是因为我认为它为前 6 个观察而不是整个数据帧计算 bbox。作为替代方案，您可以 运行 以下 print （请参阅 bbox 与完整数据集相同）：
print(nc, n = getOption("sf_max_print", default = 6))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
# First 6 features:
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
如何在不将其打印到控制台的情况下将此打印对象保存在列表中（稍后将在函数中使用）？
当我粗略地把它放在一个列表中而不试图抑制它按预期打印的输出时：
a <- lst(dim(nc), head_sf = print(nc, n = getOption("sf_max_print", default = 6)))
# Simple feature collection with 100 features and 14 fields
# geometry type: MULTIPOLYGON
# dimension: XY
# bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
# geographic CRS: NAD27
# First 6 features:
# AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry
# 1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
# 2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
# 3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
# 4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
# 5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
# 6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
我以为 invisible 或 sink 会抑制输出，但我想不通，none 这些工作：
a <- invisible(lst(dim(nc), head_sf = print(nc, n = getOption("sf_max_print", default = 6))))
a <- lst(dim(nc), head_sf = invisible(print(nc, n = getOption("sf_max_print", default = 6))))
a <- lst(dim(nc), invisible(head_sf = print(nc, n = getOption("sf_max_print", default = 6))))
有什么建议吗？谢谢
编辑：
使用 invisible 和 capture.output 几乎可以得到我想要的（当我最初发布这个时输出不正确 - 我的错误）
a <- lst(dim(nc), invisible(capture.output(head_sf = print(nc, n = getOption("sf_max_print", default = 6)))))
a
$`dim(nc)`
[1] 100 15
$`invisible(...)`
[1] "Simple feature collection with 100 features and 14 fields"
[2] "geometry type: MULTIPOLYGON"
[3] "dimension: XY"
[4] "bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965"
[5] "geographic CRS: NAD27"
[6] "First 6 features:"
[7] " AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79 geometry"
[8] "1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3..."
[9] "2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0 10 542 3 12 MULTIPOLYGON (((-81.23989 3..."
[10] "3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5 208 3616 6 260 MULTIPOLYGON (((-80.45634 3..."
[11] "4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1 123 830 2 145 MULTIPOLYGON (((-76.00897 3..."
[12] "5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3..."
[13] "6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3..."
可能是一个糟糕的方法，不知道 return 值将受到什么进一步处理（我觉得单独的暗淡，head_sf 是不可取的），如果你厌恶的话尤其糟糕循环，但使用 invisible(capture.output 的变体
library(sf)
library(tidyverse)
nc <- st_read(system.file("shape/nc.shp", package = "sf"))
nc1 <- nc
nc2 <- nc
nc3 <- nc
nc_lst <- list(nc1, nc2, nc3)
prepare_sf_head_for_further_process_loop3 <- function(nc_lst) {
a_quote <- list()
for(i in 1:length(nc_lst)) {
invisible(capture.output(a_quote[[i]] <- list(dims = dim(nc_lst[[i]]), head_sf = print(nc_lst[[i]], n = getOption('sf_max_print', default = 6)))))
}
return(a_quote)
}
>b3 <- prepare_sf_head_for_further_process_loop3(nc_lst)
>b3
[[1]]
[[1]]$dims
[1] 100 15
[[1]]$head_sf
Simple feature collection with 100 features and 14 fields
geometry type: MULTIPOLYGON
dimension: XY
bbox: xmin: -84.32385 ymin: 33.88199 xmax: -75.45698 ymax: 36.58965
geographic CRS: NAD27
First 10 features:
AREA PERIMETER CNTY_ CNTY_ID NAME FIPS FIPSNO CRESS_ID BIR74 SID74
1 0.114 1.442 1825 1825 Ashe 37009 37009 5 1091 1
2 0.061 1.231 1827 1827 Alleghany 37005 37005 3 487 0
3 0.143 1.630 1828 1828 Surry 37171 37171 86 3188 5
4 0.070 2.968 1831 1831 Currituck 37053 37053 27 508 1
5 0.153 2.206 1832 1832 Northampton 37131 37131 66 1421 9
6 0.097 1.670 1833 1833 Hertford 37091 37091 46 1452 7
7 0.062 1.547 1834 1834 Camden 37029 37029 15 286 0
8 0.091 1.284 1835 1835 Gates 37073 37073 37 420 0
9 0.118 1.421 1836 1836 Warren 37185 37185 93 968 4
10 0.124 1.428 1837 1837 Stokes 37169 37169 85 1612 1
NWBIR74 BIR79 SID79 NWBIR79 geometry
1 10 1364 0 19 MULTIPOLYGON (((-81.47276 3...
2 10 542 3 12 MULTIPOLYGON (((-81.23989 3...
3 208 3616 6 260 MULTIPOLYGON (((-80.45634 3...
4 123 830 2 145 MULTIPOLYGON (((-76.00897 3...
5 1066 1606 3 1197 MULTIPOLYGON (((-77.21767 3...
6 954 1838 5 1237 MULTIPOLYGON (((-76.74506 3...
7 115 350 2 139 MULTIPOLYGON (((-76.00897 3...
8 254 594 2 371 MULTIPOLYGON (((-76.56251 3...
9 748 1190 2 844 MULTIPOLYGON (((-78.30876 3...
10 160 2038 5 176 MULTIPOLYGON (((-80.02567 3...
>class(nc_lst[[1]]
[1] "sf" "data.frame"
>class(b3[[1]]$head_sf)
[1] "sf" "data.frame"
该死，不知道为什么 getOption('sf_max_print', default = 6) 没有限制为 6。
dplyer控制了quote/unquote，但我还没有研究出对此的应用。到目前为止，这些是我的错误建议。
另外，从 tidyverse What Hadley suggests，拿下 Hadley 并交换头部和打印，
glimpse_head2 <- function(x, n = 6) {
head(print(x, n))
invisible(x)
}
虽然这并没有变暗，但似乎比我上面的要简单得多，并且提供了所需的 bbox 值。并且仍然不限制为 6，因为 sfg 的 head 方法被硬编码为 10L:
> getS3method('head', 'sfg')
function (x, n = 10L, ...)
{
structure(head(unclass(x), n = n, ...), class = class(x))
}
<bytecode: 0x5646a6a38228>
<environment: namespace:sf>