遇到特殊字符时，从R中的字符串中提取子字符串
[英]Extract a substring from a string in R when coming across a special character
问题描述
I am trying to extract the base name (U+...) for all emoji's in a string. 
我试图在字符串中提取所有表情符号的基本名称（U + ...）。 I currently have a data frame with a column of Instagram messages (For such reasons I can't post on here for ethical reasons. However I will post a self generated one.) 我目前有一个带有一列Instagram消息的数据框（出于这些原因，由于道德原因，我不能在这里发帖。但是我会发布一个自生成的。）
I want to extract all emoji's from the messages string. 我想从消息字符串中提取所有表情符号。
So far I have been successful in using gsub to extract a single emoji from a single piece of text. 到目前为止，我已成功使用gsub从单个文本中提取单个表情符号。 For example: 例如：
gsub(".*[<]([^.]+)[>].*", "\\1", "I know <U+0001F621<U+0001F923>")
This gives me the last emoji : 这给了我最后一个表情符号：
[1] "U+0001F923"
However I'd like it to catch all emoji's in the string. 但是我希望它能捕获字符串中的所有表情符号。
like this: 像这样：
[1] "U+0001F923" [2] "U+0001F621"
Furthermore I have tried to use this gsub code to extract the data from a 2 column data frame. 此外，我尝试使用此gsub代码从2列数据框中提取数据。 (Below is a snippet from a much larger data frame) （以下是来自更大数据框的片段）
df: DF：
name value
<chr> <chr>
Participant1 instahandle1
Participant2 instahandle2
conversation.sender instahandle2
conversation.created_at 2019-03-24T19:08:25.632223+00:00
conversation.text I know <U+0001F923><U+0001F923>x
conversation.sender instahandle1
conversation.created_at 2019-03-24T19:04:01.042261+00:00
conversation.text Me too! it was cool
conversation.sender instahandle2
conversation.created_at 2019-03-24T19:03:42.065983+00:00
gsub(".*[<]([^.]+)[>].*", "\\1", df$value)
However this just retrieves. 然而，这只是检索。
[1] "instahandle1"
[2] "instahandle2"
[3] "instahandle2"
[4] "2019-03-24T19:08:25.632223+00:00"
[5] "I know \U0001f923\U0001f923x"
[6] "instahandle1"
[7] "2019-03-24T19:04:01.042261+00:00"
[8] "Me too! it was cool"
[9] "instahandle2"
[10] "2019-03-24T19:03:42.065983+00:00"
I would like it to extract every emoji and nothing else. 我希望它能提取每一个表情符号，而不是其他任何东西。 like this: 像这样：
[1] "U+0001F923" [2] "U+0001F621"
2 个解决方案
解决方案1
2 已采纳 2019-07-24 11:55:03
You may use 你可以用
x <- "I know \U0001F621\U0001F923s"
regmatches(x, gregexpr("[^[:ascii:]]+", x, perl=TRUE))
## => [[1]]
## [1] "😡🤣"
This code extracts all non-ASCII char chunks from the input. 此代码从输入中提取所有非ASCII char块。 See the online R demo . 查看在线R演示 。
Since [:ascii:] character class is not POSIX compliant, perl=TRUE is required. 由于[:ascii:]字符类不符合POSIX，因此需要perl=TRUE 。
If you want to extract only emojis separately use 如果你想只提取表情符号分开使用
emoji_rx <- "[\\x{1f300}-\\x{1f5ff}\\x{1f900}-\\x{1f9ff}\\x{1f600}-\\x{1f64f}\\x{1f680}-\\x{1f6ff}\\x{2600}-\\x{26ff}\\x{2700}-\\x{27bf}\\x{1f1e6}-\\x{1f1ff}\\x{1f191}-\\x{1f251}\\x{1f004}\\x{1f0cf}\\x{1f170}-\\x{1f171}\\x{1f17e}-\\x{1f17f}\\x{1f18e}\\x{3030}\\x{2b50}\\x{2b55}\\x{2934}-\\x{2935}\\x{2b05}-\\x{2b07}\\x{2b1b}-\\x{2b1c}\\x{3297}\\x{3299}\\x{303d}\\x{00a9}\\x{00ae}\\x{2122}\\x{23f3}\\x{24c2}\\x{23e9}-\\x{23ef}\\x{25b6}\\x{23f8}-\\x{23fa}]"
x <- "I know \U0001F621\U0001F923s"
regmatches(x, gregexpr(emoji_rx, x, perl=TRUE))
## => [[1]]
## [1] "😡" "🤣"
## Or, to get them as single chunks
emoji_rx <- "[\\x{1f300}-\\x{1f5ff}\\x{1f900}-\\x{1f9ff}\\x{1f600}-\\x{1f64f}\\x{1f680}-\\x{1f6ff}\\x{2600}-\\x{26ff}\\x{2700}-\\x{27bf}\\x{1f1e6}-\\x{1f1ff}\\x{1f191}-\\x{1f251}\\x{1f004}\\x{1f0cf}\\x{1f170}-\\x{1f171}\\x{1f17e}-\\x{1f17f}\\x{1f18e}\\x{3030}\\x{2b50}\\x{2b55}\\x{2934}-\\x{2935}\\x{2b05}-\\x{2b07}\\x{2b1b}-\\x{2b1c}\\x{3297}\\x{3299}\\x{303d}\\x{00a9}\\x{00ae}\\x{2122}\\x{23f3}\\x{24c2}\\x{23e9}-\\x{23ef}\\x{25b6}\\x{23f8}-\\x{23fa}]+"
regmatches(x, gregexpr(emoji_rx, x, perl=TRUE))
## => [[1]]
## [1] "😡🤣"
See this online R demo . 看到这个在线R演示 。
解决方案2
0 2019-07-24 10:31:24
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