删除NA |时出现R问题没有检测到NA，用is.na找不到

Question

不明白为什么不能检测或删除列时间戳中的所有NA。虽然我通过查询删除了所有NA，但是仍然在我的数据中，但是查询无法检测到，但是在数据查看器中显示。详情请见下文：

在列时间戳中，我从列visit_start_time_gmt创建了一个日期时间（这是一个Unix时间戳）：

data_1<-cbind(data_1,anytime(as.numeric(as.character(data_1$visit_start_time_gmt))))

一些NAs出现了，其中删除了：

data_1<-data_1[!is.na(data_1$timestamp),]

并且，正如预期的那样，以下结果为0：

nrow(data_1[is.na(data_1$timestamp),]) 

我想知道，以下查询仍会导致NA：

max(data_1$timestamp)

因此，我确实看了一下数据查看器，并且仍然惊讶地看到4个NAs：

在以下行中：

我完全感到困惑的是，按行号删除这些行不起作用（在尝试删除此方式后，NA仍在我的数据中）：

data_1<-data_1[-c(788748,94812,94819,94825),] 

它只能通过我自己的列index_id删除

data_1<-data_1[!data_1$index_id %in% c(788748,94812,94819,94825),]

是什么导致这个尴尬的问题？如何以正确的方式检测和删除所有的NA？

在这里，您可以创建数据（包括列时间戳中的4个不可检测的NA）：

head(dput(data_1[c(1:10),]))

    structure(list(index_id = c(94812L, 94814L, 94815L, 94816L, 94817L, 
94818L, 94819L, 94821L, 94822L, 94823L, 94824L, 94825L, 94827L, 
94828L, 94829L, 94830L, 94831L, 94832L, 94833L, 94834L, 94835L, 
94836L, 94837L, 94838L, 94839L, 94840L, 94841L, 94842L, 94843L, 
94844L, 94845L, 94846L, 94847L, 94848L, 94849L, 94850L, 94851L, 
94852L, 94853L, 94854L, 94855L, 94856L, 94857L, 94858L, 94859L, 
94860L, 94861L, 94862L, 94863L, 94864L, 94865L), campaign = c("", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", ""), exclude_hit = c("0", "0", "0", "0", "0", "0", "0", "0", 
"0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", 
"0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", 
"0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", 
"0", "0", "0", "0"), first_hit_page_url = c("http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/", "http://www.samsung.com/de/", "http://www.samsung.com/de/", 
"http://www.samsung.com/de/mobile-content-page/", "http://www.samsung.com/de/mobile-content-page/", 
"http://www.samsung.com/de/mobile-content-page/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/consumer/mobile-devices/accessories/power/EP-PG920IBEGWW", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/mobile-content-page/"
), first_hit_pagename = c("de:home", "de:home", "de:home", "de:home", 
"de:home", "de:home", "de:home", "de:home", "de:home", "de:home", 
"de:home", "de:home", "de:home", "de:home", "de:home", "de:home", 
"de:home", "de:home", "de:home", "de:home", "de:home", "de:home", 
"de:home", "de:home", "de:home", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:contents", "de:contents", "de:contents", 
"de:contents", "de:contents", "de:contents", "de:contents", "de:contents", 
"de:contents", "de:contents", "de:contents", "de:contents", "de:contents", 
"de:contents", "de:contents", "de:contents", "de:contents", "de:contents", 
"de:contents", "de:contents", "de:consumer:mobile devices:accessories:power:ep-pg920ibegww", 
"de:contents", "de:mobile-content-page"), first_hit_ref_domain = c("", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", ""), first_hit_ref_type = c("1", "1", "1", "1", "1", "1", 
"1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1", "1", "1", "1", "6", "6", "6", "6", "6", "6", "6", 
"6", "6", "6", "6", "6", "6", "6", "6", "6", "6", "6", "6", "6", 
"6", "6", "6", "6", "6", "6"), first_hit_referrer = c("http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"http://www.samsung.com/de/contents/", "http://www.samsung.com/de/contents/", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", ""), first_hit_time_gmt = c("1515600363", 
"1515600363", "1515600363", "1515600363", "1515600363", "1515600363", 
"1515600363", "1515600363", "1515600363", "1515600363", "1515600363", 
"1515600363", "1515600363", "1515600363", "1515600363", "1515600363", 
"1515600363", "1515600363", "1515600363", "1515600363", "1515600363", 
"1515600363", "1515600363", "1515600363", "1515600363", "1525596576", 
"1525596576", "1525596576", "1463949764", "1463954663", "1463974801", 
"1463987199", "1464000142", "1464036391", "1464123965", "1464124564", 
"1464132646", "1464136256", "1464136256", "1464170611", "1464191265", 
"1464191265", "1464201356", "1464207203", "1464207203", "1464207203", 
"1464212475", "1464212475", "1464212493", "1464212984", "1521765893"
), hit_source = c("1", "1", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1"), post_campaign = c("", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
"", "", "", "", "", "", "", "", "", "", "", ""), post_cust_hit_time_gmt = c("", 
"1525737195", "1525737206", "1525737301", "1525737305", "1525737309", 
"", "1525737331", "1525737346", "1525737358", "1525737388", "", 
"1525737397", "1525737398", "1525737412", "1525737424", "1525737434", 
"1525737448", "1525737521", "1525737526", "1525737534", "1525737557", 
"1525737561", "1525737565", "1525737579", "1525736201", "1525736229", 
"1525736426", "1525736763", "1525737360", "1525736174", "1525736723", 
"1525736207", "1525736839", "1525737132", "1525736460", "1525737437", 
"1525737070", "1525737322", "1525736704", "1525737233", "1525737237", 
"1525737179", "1525736066", "1525736117", "1525736374", "1525735974", 
"1525736045", "1525737342", "1525735841", "1525736055"), post_page_url = c("", 
"http://www.samsung.com/de/support/newsalert/101154", "", "http://www.samsung.com/de/support/newsalert?filter=alert", 
"", "http://www.samsung.com/de/support/newsalert?filter=alert", 
"", "http://www.samsung.com/de/support/newsalert/100844", "", 
"http://www.samsung.com/de/support/smart-simulator", "http://www.samsung.com/de/support/newsalert?filter=alert", 
"", "http://www.samsung.com/de/support/newsalert/100844", "", 
"", "", "http://www.samsung.com/de/support/smart-simulator", 
"", "", "http://www.samsung.com/de/support/newsalert/100811", 
"", "http://www.samsung.com/de/support/newsalert?filter=alert", 
"http://www.samsung.com/de/support/smartswitch", "http://www.samsung.com/de/mobile-content-page", 
"", "http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de", "http://www.samsung.com/de", "", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page", "http://www.samsung.com/de/mobile-content-page", 
"http://www.samsung.com/de/mobile-content-page"), post_pagename = c("", 
"de:support:newsalert:101154", "", "de:support:newsalert", "", 
"de:support:newsalert", "", "de:support:newsalert:100844", "", 
"de:support:smart-simulator", "de:support:newsalert", "", "de:support:newsalert:100844", 
"", "", "", "de:support:smart-simulator", "", "", "de:support:newsalert:100811", 
"", "de:support:newsalert", "de:support:smartswitch", "de:mobile-content-page", 
"", "de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:home", 
"de:home", "", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page"), post_visid_high = c("", "3143668157394264962", 
"3143668157394264962", "3143668157394264962", "3143668157394264962", 
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"4611689327162988203", "6917532342819023626", "2636988164942374912"
), va_closer_detail = c("8/4/2018 1:53:9 2 -120", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "8/4/2018 1:55:26 2 -120", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
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"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "n:Google - Germany:::empty::", 
"de:contents", "de:mobile-content-page", "de:mobile-content-page", 
"n:Google - Germany:::empty::", "de:contents", "p:Google - Germany:::empty::", 
"n:Google - Germany:::empty::", "n:Google - Germany:::empty::", 
"de:contents", "de:contents", "de:home", "de:home", "de:home", 
"de:contents", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "n:Google - Germany:::empty::", "n:Google - Germany:::empty::", 
"de:mobile-content-page", "de:contents", "de:mobile-content-page"
), va_closer_id = c("", "5", "5", "5", "5", "5", "", "5", "5", 
"5", "5", "", "5", "5", "5", "5", "5", "5", "5", "5", "5", "5", 
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"2", "2", "6", "6", "6", "6", "6", "5", "5", "5", "5", "2", "2", 
"5", "5", "5"), va_finder_detail = c("", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:mobile-content-page", "de:mobile-content-page", 
"de:contents", "de:contents", "de:mobile-content-page", "de:mobile-content-page", 
"de:contents", "de:contents", "de:contents", "de:contents", "de:contents", 
"de:contents", "de:contents", "de:home", "de:home", "de:home", 
"de:contents", "de:mobile-content-page", "de:mobile-content-page", 
"de:mobile-content-page", "de:home", "de:home", "de:mobile-content-page", 
"de:contents", "de:mobile-content-page"), va_finder_id = c("", 
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"5", "5", "5", "5", "5", "5", "5", "5", "5", "5", "5", "5", "5", 
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"6", "6", "6", "6", "6", "", "6", "6", "6", "6", "", "6", "6", 
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"256", "915", "915", "29", "151", "151", "1296", "843", "843", 
"843", "906", "906", "23", "536", "62"), visit_page_num = c("", 
"10", "11", "12", "13", "14", "", "16", "17", "18", "19", "", 
"21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", 
"32", "33", "1", "2", "3", "1", "1", "1", "1", "1", "1", "1", 
"1", "1", "1", "2", "1", "1", "2", "1", "1", "2", "3", "2", "3", 
"1", "1", "1"), visit_start_time_gmt = c("3143668157394264962", 
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"1525736927", "1525736201", "1525736201", "1525736201", "1525736763", 
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"1525736066", "1525736066", "1525735643", "1525735643", "1525737342", 
"1525735841", "1525736055"), timestamp = structure(c(3143668157394265088, 
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1525736927, 1525736927, 1525736927, 1525736927, 3143668157394265088, 
1525736927, 1525736927, 1525736927, 1525736927, 1525736927, 1525736927, 
1525736927, 1525736927, 1525736927, 1525736927, 1525736927, 1525736927, 
1525736927, 1525736201, 1525736201, 1525736201, 1525736763, 1525737360, 
1525736174, 1525736723, 1525736207, 1525736839, 1525737132, 1525736460, 
1525737437, 1525737070, 1525737070, 1525736704, 1525737233, 1525737233, 
1525737179, 1525736066, 1525736066, 1525736066, 1525735643, 1525735643, 
1525737342, 1525735841, 1525736055), class = c("POSIXct", "POSIXt"
), tzone = "UTC")), .Names = c("index_id", "campaign", "exclude_hit", 
"first_hit_page_url", "first_hit_pagename", "first_hit_ref_domain", 
"first_hit_ref_type", "first_hit_referrer", "first_hit_time_gmt", 
"hit_source", "post_campaign", "post_cust_hit_time_gmt", "post_page_url", 
"post_pagename", "post_visid_high", "post_visid_low", "va_closer_detail", 
"va_closer_id", "va_finder_detail", "va_finder_id", "visit_num", 
"visit_page_num", "visit_start_time_gmt", "timestamp"), row.names = c(94812L, 
94814L, 94815L, 94816L, 94817L, 94818L, 94819L, 94821L, 94822L, 
94823L, 94824L, 94825L, 94827L, 94828L, 94829L, 94830L, 94831L, 
94832L, 94833L, 94834L, 94835L, 94836L, 94837L, 94838L, 94839L, 
94840L, 94841L, 94842L, 94843L, 94844L, 94845L, 94846L, 94847L, 
94848L, 94849L, 94850L, 94851L, 94852L, 94853L, 94854L, 94855L, 
94856L, 94857L, 94858L, 94859L, 94860L, 94861L, 94862L, 94863L, 
94864L, 94865L), class = "data.frame")

Answer 1

dput(data_1$timestamp[1])
#structure(3143668157394265088, class = c("POSIXct", "POSIXt"), tzone = "UTC")

好的，不是NA。

让我们来研究help("POSIXct")：

在所有已知的64位平台和我们在32位Windows上使用的代码中，可表示的时间范围是数十亿年：...

unclass(data_1$timestamp[1])/3600/24/365
#[1] 99685063337
#attr(,"tzone")
#[1] "UTC

这是数十亿年，而且很少。

好吧，print.POSIXct称format.POSIXct内部胁迫POSIXlt。现在，看看POSIXlt对象的组件：

lapply(unclass(as.POSIXlt("2018-01-01")), class)
#$`sec`
#[1] "numeric"
#
#$min
#[1] "integer"
#
#$hour
#[1] "integer"
#
#$mday
#[1] "integer"
#
#$mon
#[1] "integer"
#
#$year
#[1] "integer"
#
#$wday
#[1] "integer"
#
#$yday
#[1] "integer"
#
#$isdst
#[1] "integer"
#
#$zone
#[1] "character"
#
#$gmtoff
#[1] "integer"

年份存储为整数。

.Machine$integer.max
#[1] 2147483647

这比您拥有的年数少，因此as.POSIXlt将您的日期时间转换为NA，并且为这些NA对象打印POSIXct。

我认为您需要修复日期时间解析步骤。不要指望来自qazxsw poi的奇迹。