我有一个数据框列表（下面的示例），其中数据是关于每个州的医院列表。
outcome_split是一个列表，其中包含每个州的数据框列表。rank中添加了一个AL列，该列对该特定州的所有医院进行排名，同样（使用for循环）我会向所有人添加一个排名变量列表中的数据框。如上所述，第二个元素具有秩变量，因此我尝试调用该元素并匹配指定的等级。我是初学者，我觉得我很困惑＆＃39; ==＆＃39;和＆＃39; =＆＃39;。
> outcome_split[[2]][, "hospital name"]["rank"==2]
character(0)
> outcome_split[[2]][, "hospital name"]["rank"=7]
[1] "BIBB MEDICAL CENTER"
我想返回符合指定级别的医院名称，但我不知道该怎么做。正如之前所说，混淆了＆＃39; ==＆＃39;和＆＃39; =＆＃39;因为＆＃39; ==＆＃39;返回character(0)，而＆＃39; =＆＃39;在第二个元素中返回医院的名称，但是这个返回不是基于排名变量而是基于ID值，在第7位，所提到的医院存在，但它没有排名第7位。
> outcome_split[[2]][, c("hospital name","rank")]
hospital name rank
1 ANDALUSIA REGIONAL HOSPITAL 52
2 ATHENS-LIMESTONE HOSPITAL 9
3 ATMORE COMMUNITY HOSPITAL 53
4 BAPTIST MEDICAL CENTER EAST 2
5 BAPTIST MEDICAL CENTER SOUTH 46
6 BAPTIST MEDICAL CENTER-PRINCETON 8
7 BIBB MEDICAL CENTER 54
8 BIRMINGHAM VA MEDICAL CENTER 26
9 BROOKWOOD MEDICAL CENTER 30
10 BRYAN W WHITFIELD MEM HOSP INC 55
示例数据：
outcome_split <- structure(list(AK = structure(list(`hospital name` = c("PROVIDENCE ALASKA MEDICAL CENTER",
"MAT-SU REGIONAL MEDICAL CENTER", "BARTLETT REGIONAL HOSPITAL",
"FAIRBANKS MEMORIAL HOSPITAL", "ALASKA REGIONAL HOSPITAL", "YUKON KUSKOKWIM DELTA REG HOSPITAL",
"CENTRAL PENINSULA GENERAL HOSPITAL", "ALASKA NATIVE MEDICAL CENTER",
"MT EDGECUMBE HOSPITAL", "PROVIDENCE VALDEZ MEDICAL CENTER",
"PROVIDENCE SEWARD HOSPITAL", "SITKA COMMUNITY HOSPITAL", "PROVIDENCE KODIAK ISLAND MEDICAL CTR",
"CORDOVA COMMUNITY MEDICAL CENTER", "NORTON SOUND REGIONAL HOSPITAL",
"PEACEHEALTH KETCHIKAN MEDICAL CENTER", "SOUTH PENINSULA HOSPITAL"
), state = c("AK", "AK", "AK", "AK", "AK", "AK", "AK", "AK",
"AK", "AK", "AK", "AK", "AK", "AK", "AK", "AK", "AK"), `heart attack` = c("13.4",
"17.7", "Not Available", "15.5", "14.5", "Not Available", "Not Available",
"15.7", "Not Available", "Not Available", "Not Available", "Not Available",
"Not Available", "Not Available", "Not Available", "Not Available",
"Not Available"), `heart failure` = c("12.4", "11.4", "11.6",
"15.6", "13.4", "11.2", "11.6", "11.6", "Not Available", "Not Available",
"Not Available", "Not Available", "Not Available", "Not Available",
"Not Available", "11.4", "10.8"), pneumonia = c("10.5", "12.1",
"11.6", "13.4", "12.5", "9.7", "13.8", "15.5", "14.2", "Not Available",
"Not Available", "11.5", "12.0", "Not Available", "11.6", "11.3",
"12.2")), .Names = c("hospital name", "state", "heart attack",
"heart failure", "pneumonia"), row.names = 99:115, class = "data.frame"),
AL = structure(list(`hospital name` = c("ANDALUSIA REGIONAL HOSPITAL",
"ATHENS-LIMESTONE HOSPITAL", "ATMORE COMMUNITY HOSPITAL",
"BAPTIST MEDICAL CENTER EAST", "BAPTIST MEDICAL CENTER SOUTH",
"BAPTIST MEDICAL CENTER-PRINCETON", "BIBB MEDICAL CENTER",
"BIRMINGHAM VA MEDICAL CENTER", "BROOKWOOD MEDICAL CENTER",
"BRYAN W WHITFIELD MEM HOSP INC", "BULLOCK COUNTY HOSPITAL",
"CALLAHAN EYE FOUNDATION HOSPITAL", "CHEROKEE MEDICAL CENTER",
"CHILTON MEDICAL CENTER", "CITIZENS BAPTIST MEDICAL CENTER",
"CLAY COUNTY HOSPITAL", "COMMUNITY HOSPITAL INC", "COOPER GREEN MERCY HOSPITAL",
"COOSA VALLEY MEDICAL CENTER", "CRENSHAW COMMUNITY HOSPITAL",
"CRESTWOOD MEDICAL CENTER", "CULLMAN REGIONAL MEDICAL CENTER",
"D C H REGIONAL MEDICAL CENTER", "D W MCMILLAN MEMORIAL HOSPITAL",
"DALE MEDICAL CENTER", "DECATUR GENERAL HOSPITAL", "DEKALB REGIONAL MEDICAL CENTER",
"EAST ALABAMA MEDICAL CENTER AND SNF", "ELBA GENERAL HOSPITAL",
"ELIZA COFFEE MEMORIAL HOSPITAL", "ELMORE COMMUNITY HOSPITAL",
"EVERGREEN MEDICAL CENTER", "FAYETTE MEDICAL CENTER", "FLORALA MEMORIAL HOSPITAL",
"FLOWERS HOSPITAL", "GADSDEN REGIONAL MEDICAL CENTER", "GEORGE H. LANIER MEMORIAL HOSPITAL",
"GEORGIANA HOSPITAL", "GREENE COUNTY HOSPITAL", "GROVE HILL MEMORIAL HOSPITAL",
"HALE COUNTY HOSPITAL", "HELEN KELLER MEMORIAL HOSPITAL",
"HIGHLANDS MEDICAL CENTER", "HILL HOSPITAL OF SUMTER COUNTY",
"HUNTSVILLE HOSPITAL", "INFIRMARY WEST", "J PAUL JONES HOSPITAL",
"JACK HUGHSTON MEMORIAL HOSPITAL", "JACKSON HOSPITAL & CLINIC INC",
"JACKSON MEDICAL CENTER", "JACKSONVILLE MEDICAL CENTER",
"L V STABLER MEMORIAL HOSPITAL", "LAKE MARTIN COMMUNITY HOSPITAL",
"LAKELAND COMMUNITY HOSPITAL", "LAWRENCE MEDICAL CENTER",
"MARION REGIONAL MEDICAL CENTER", "MARSHALL MEDICAL CENTER NORTH",
"MARSHALL MEDICAL CENTER SOUTH", "MEDICAL CENTER BARBOUR",
"MEDICAL CENTER ENTERPRISE", "MEDICAL WEST, AN AFFILIATE OF UAB HEALTH SYSTEM",
"MIZELL MEMORIAL HOSPITAL", "MOBILE INFIRMARY", "MONROE COUNTY HOSPITAL",
"NORTH BALDWIN INFIRMARY", "NORTHEAST ALABAMA REGIONAL MED CENTER",
"NORTHWEST MEDICAL CENTER", "PARKWAY MEDICAL CENTER", "PICKENS COUNTY MEDICAL CENTER",
"PRATTVILLE BAPTIST HOSPITAL", "PROVIDENCE HOSPITAL", "RED BAY HOSPITAL",
"RIVERVIEW REGIONAL MEDICAL CENTER", "RUSSELL HOSPITAL",
"RUSSELLVILLE HOSPITAL", "SHELBY BAPTIST MEDICAL CENTER",
"SHOALS HOSPITAL", "SOUTH BALDWIN REGIONAL MEDICAL CENTER",
"SOUTHEAST ALABAMA MEDICAL CENTER", "SPRINGHILL MEDICAL CENTER",
"ST VINCENT'S BIRMINGHAM", "ST VINCENT'S EAST", "ST VINCENT'S ST CLAIR",
"ST VINCENTS BLOUNT", "STRINGFELLOW MEMORIAL HOSPITAL", "THOMAS HOSPITAL",
"TRINITY MEDICAL CENTER", "TROY REGIONAL MEDICAL CENTER",
"TUSCALOOSA VA MEDICAL CENTER", "UNIV OF S AL CHILDREN'S & WOMEN'S HOS",
"UNIV OF SOUTH ALABAMA MEDICAL CENTER", "UNIVERSITY OF ALABAMA HOSPITAL",
"VA CENTRAL ALABAMA HEALTHCARE SYSTEM - MONTGOMERY", "VAUGHAN REG MED CENTER PARKWAY CAMPUS",
"WALKER BAPTIST MEDICAL CENTER", "WASHINGTON COUNTY HOSPITAL",
"WEDOWEE HOSPITAL", "WIREGRASS MEDICAL CENTER"), state = c("AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL", "AL",
"AL", "AL", "AL", "AL", "AL", "AL", "AL"), `heart attack` = c("Not Available",
"15.0", "Not Available", "14.2", "17.8", "14.9", "Not Available",
"16.1", "16.5", "Not Available", "Not Available", "Not Available",
"Not Available", "Not Available", "17.3", "16.7", "17.1",
"Not Available", "15.2", "Not Available", "13.3", "17.1",
"15.8", "15.7", "17.3", "16.8", "18.0", "16.3", "Not Available",
"18.1", "Not Available", "Not Available", "16.7", "Not Available",
"15.2", "16.7", "15.4", "14.5", "Not Available", "Not Available",
"Not Available", "19.6", "15.0", "Not Available", "15.2",
"Not Available", "Not Available", "Not Available", "17.5",
"Not Available", "Not Available", "Not Available", "Not Available",
"Not Available", "15.6", "Not Available", "Not Available",
"18.5", "Not Available", "16.6", "15.3", "Not Available",
"19.3", "Not Available", "Not Available", "15.6", "Not Available",
"15.8", "Not Available", "14.6", "15.2", "Not Available",
"16.9", "17.1", "Not Available", "15.9", "Not Available",
"15.8", "14.3", "16.0", "16.2", "17.7", "Not Available",
"Not Available", "16.4", "14.7", "16.8", "Not Available",
"Not Available", "Not Available", "Not Available", "15.0",
"Not Available", "14.7", "17.0", "Not Available", "Not Available",
"Not Available"), `heart failure` = c("10.1", "11.7", "10.8",
"9.6", "11.8", "11.4", "14.0", "10.4", "13.5", "11.7", "12.3",
"Not Available", "12.1", "11.5", "14.9", "12.6", "12.3",
"Not Available", "11.7", "13.8", "13.8", "12.1", "11.2",
"14.8", "11.8", "10.9", "16.6", "12.9", "Not Available",
"11.3", "11.3", "9.1", "11.7", "10.4", "12.0", "10.7", "8.8",
"10.8", "11.2", "10.4", "10.7", "12.6", "13.4", "Not Available",
"12.4", "12.5", "Not Available", "10.8", "10.2", "12.3",
"16.4", "11.1", "10.9", "13.6", "9.9", "11.5", "12.5", "15.2",
"13.5", "12.9", "11.4", "13.6", "10.7", "13.0", "11.5", "11.2",
"11.8", "10.5", "12.6", "14.8", "13.5", "12.6", "10.8", "11.6",
"14.8", "13.6", "13.6", "15.1", "11.4", "10.4", "10.6", "10.9",
"10.8", "13.0", "12.0", "12.8", "12.9", "11.2", "Not Available",
"Not Available", "12.5", "12.5", "12.2", "12.0", "10.8",
"Not Available", "10.4", "10.6"), pneumonia = c("11.1", "12.1",
"13.0", "10.2", "14.3", "11.6", "13.6", "11.0", "13.0", "9.1",
"12.1", "Not Available", "14.7", "11.2", "12.1", "11.8",
"11.6", "Not Available", "11.4", "15.8", "10.4", "12.1",
"11.3", "12.6", "9.9", "11.9", "15.8", "12.1", "12.0", "13.4",
"11.2", "12.0", "12.9", "12.1", "11.3", "14.6", "10.3", "11.3",
"11.5", "12.1", "11.5", "15.0", "12.9", "Not Available",
"14.1", "13.1", "11.4", "10.9", "14.7", "9.3", "19.2", "13.0",
"10.8", "10.7", "9.8", "10.0", "8.7", "13.9", "15.0", "12.9",
"12.1", "14.9", "12.5", "15.6", "14.6", "13.2", "13.1", "11.9",
"12.4", "14.2", "10.6", "11.6", "12.7", "14.9", "11.5", "10.7",
"12.8", "9.8", "10.9", "13.8", "12.6", "16.2", "11.4", "15.3",
"12.0", "13.1", "13.9", "11.1", "Not Available", "Not Available",
"Not Available", "12.7", "11.3", "14.0", "11.9", "Not Available",
"13.9", "12.3"), rank = c(52L, 9L, 53L, 2L, 46L, 8L, 54L,
26L, 30L, 55L, 56L, 57L, 58L, 59L, 42L, 32L, 39L, 60L, 12L,
61L, 1L, 40L, 21L, 20L, 43L, 35L, 47L, 28L, 62L, 48L, 63L,
64L, 33L, 65L, 13L, 34L, 17L, 4L, 66L, 67L, 68L, 51L, 10L,
69L, 14L, 70L, 71L, 72L, 44L, 73L, 74L, 75L, 76L, 77L, 18L,
78L, 79L, 49L, 80L, 31L, 16L, 81L, 50L, 82L, 83L, 19L, 84L,
22L, 85L, 5L, 15L, 86L, 37L, 41L, 87L, 24L, 88L, 23L, 3L,
25L, 27L, 45L, 89L, 90L, 29L, 6L, 36L, 91L, 92L, 93L, 94L,
11L, 95L, 7L, 38L, 96L, 97L, 98L)), class = "data.frame", .Names = c("hospital name",
"state", "heart attack", "heart failure", "pneumonia", "rank"
), row.names = c(NA, -98L))), .Names = c("AK", "AL"))
答案 0 :(得分：1)
如果要从第二个列表元素中选择等级2和7，请尝试：
outcome_split[[2]][outcome_split[[2]]$rank == 2, c("hospital name", "rank")]
医院名称等级
4 BAPTIST MEDICAL CENTER EAST 2
outcome_split[[2]][outcome_split[[2]]$rank == 7, c("hospital name", "rank")]
医院名称等级
94 VAUGHAN REG MED CENRE PARKWAY CAMPUS 7
我建议将列表折叠到data.frame，因为这会使过滤变得更加容易。尝试搜索dplyr::bind_rows或do.call("rbind")
答案 1 :(得分：1)
您的rank列未按顺序排列，请参阅下面按排名排列的位置。
选择是带有dplyr的单行（或使用data.table）：
require(dplyr)
output_split[[2]] %>% filter(rank == 2) %>% select('hospital name')
hospital name
1 BAPTIST MEDICAL CENTER EAST
output_split[[2]] %>% filter(rank == '7') %>% select('hospital name')
hospital name
1 VAUGHAN REG MED CENTER PARKWAY CAMPUS
# Here's the hospital order when we arrange by 'rank':
output_split[[2]] %>% arrange(rank) %>% select('hospital name', 'rank') %>% head(7)
hospital name rank
1 CRESTWOOD MEDICAL CENTER 1
2 BAPTIST MEDICAL CENTER EAST 2
3 SOUTHEAST ALABAMA MEDICAL CENTER 3
4 GEORGIANA HOSPITAL 4
5 PRATTVILLE BAPTIST HOSPITAL 5
6 THOMAS HOSPITAL 6
7 VAUGHAN REG MED CENTER PARKWAY CAMPUS 7
# ... and here was your original order
output_split[[2]] %>% select('hospital name', 'rank') %>% head(7)
hospital name rank
1 ANDALUSIA REGIONAL HOSPITAL 52
2 ATHENS-LIMESTONE HOSPITAL 9
3 ATMORE COMMUNITY HOSPITAL 53
4 BAPTIST MEDICAL CENTER EAST 2
5 BAPTIST MEDICAL CENTER SOUTH 46
6 BAPTIST MEDICAL CENTER-PRINCETON 8
7 BIBB MEDICAL CENTER 54
顺便说一句，为了避免麻烦，请使用下划线而不是列名称中的空格，然后我们不需要围绕＆lt; hospital_name＆＃39;等
names(os[[2]]) <- gsub(' ', '_', names(os[[2]])))重命名它们
"hospital_name" "state" "heart_attack" "heart_failure" "pneumonia" "rank"
或者你可以使用make.names()来破坏除字母数字，下划线和点之外的任何字符。和gsub（）如果你想要更好的控制。
您可以将dfs列表折叠为一个大df：
output_split[[1]]$rank <- NA
do.call(function(...) rbind(..., make.row.names=F), output_split)
那样做。现在您的dplyr选择只是%>% filter(state=='AL', rank==2) %>% select('hospital name')