[英]R data.table %like% with logical AND
I am trying to build a Shiny app that is a search engine. 我正在尝试构建一个搜索引擎的Shiny应用程序。 I am returning a data.table based on the search keywords:
我根据搜索关键字返回data.table:
DT <- data.table(field = c("A_B_C","A_C_D","A_D_A","B_A_D","B_C_F","B_D_K"))
DT[field %like% "A|B"]
The above returns all fields containing A OR B. If I want to have A & B: 以上内容返回包含A或B的所有字段。如果我想要A和B:
DT[field %like% "A"][field %like% "B"]
Is there a syntax that will allow me to do the above for any number of keywords. 是否有一种语法允许我对任意数量的关键字执行上述操作。 Something like:
就像是:
DT[field %like% "A & B & C"]
If there are only two elements, compare them separately, then do a &
and subset the dataset 如果只有两个元素,请单独比较它们,然后执行
&
和子集数据集
DT[field %like% "A" & field %like% "B"]
# field
#1: A_B_C
#2: B_A_D
If there are many strings to compare use Reduce
with Map
. 如果要比较许多字符串,请使用
Reduce
和Map
。
DT[Reduce(`&`, Map(`%like%`, list(field), c("A", "B")))]
# field
#1: A_B_C
#2: B_A_D
Or you can use Perl-style regex, in combination with grepl
inside your data.table
: 或者你可以使用Perl的正则表达式的风格 ,结合
grepl
您的内部data.table
:
pat <- "(?=.*A)(?=.*B)"
DT[grep(pat, field, perl = TRUE),]
# field
#1: A_B_C
#2: B_A_D
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