Question

我有两个数据框，第一个（dt）包含所有chr，第二个（TargetWord）是包含chr的字典也是。我使用pmatch在dt中搜索了TargetWord中可用的字词，并从TargetWord返回了该字词。当数据帧很小时，它工作正常。 但问题在数据帧很大时开始，它只返回第一列的单词位置，其余列变为NA 。

## Data Table
word_1 <- c("conflict","", "resolved", "", "", "")
word_2 <- c("", "one", "tricky", "one", "", "one")
word_3 <- c("thanks","", "", "comments", "par","")
word_4 <- c("thanks","", "", "comments", "par","")
word_5 <- c("", "one", "tricky", "one", "", "one")
dt <- data.frame(word_1, word_2, word_3,word_4, word_5, stringsAsFactors = FALSE)

## Targeted Words
TargetWord <- data.frame(cbind(c("conflict", "thanks", "tricky", "one", "two", "three")))

## convert into matrix (needed)
dt <- as.matrix(dt)
TargetWord <- as.matrix(TargetWord)

result <- `dim<-`(pmatch(dt, TargetWord, duplicates.ok=TRUE), dim(dt))
print(result)

返回结果，

     [,1] [,2] [,3] [,4] [,5]
[1,]    1   NA    2    2   NA
[2,]   NA    4   NA   NA    4
[3,]   NA    3   NA   NA    3
[4,]   NA    4   NA   NA    4
[5,]   NA   NA   NA   NA   NA
[6,]   NA    4   NA   NA    4

现在，在阅读了两个.csv之后，结果仅适用于我想要的所有列的第一列，例如上面的结果。 Bellow，dt1 = 79 * 50数据帧，以及word_dict 13901 * 1数据帧。

#################### on big data #####################################
dt1 <- read.csv("C:/Users/Wonderland/Downloads/string_feature.csv", stringsAsFactors = FALSE)
word_dict <- read.csv("C:/Users/Wonderland/Downloads/word_dict.csv", stringsAsFactors = FALSE)

dt1 <- as.matrix(dt1)
word_dict <- as.matrix(word_dict)

result <- `dim<-`(pmatch(dt1, word_dict, duplicates.ok=TRUE), dim(dt1))
print(result)

Answer 1

尝试申请：

apply(dt,2,function(x) pmatch(x,TargetWord,duplicates.ok = T))

正如您所看到的，结果是相同的，但它可能适用于庞大的数据框

     word_1 word_2 word_3 word_4 word_5
[1,]      1     NA      2      2     NA
[2,]     NA      4     NA     NA      4
[3,]     NA      3     NA     NA      3
[4,]     NA     NA     NA     NA     NA
[5,]     NA     NA     NA     NA     NA
[6,]     NA     NA     NA     NA     NA

我尝试过：

word_1 <- rep(c("conflict","", "resolved", "", "", ""),1000)
word_2 <- rep(c("", "one", "tricky", "one", "", "one"),1000)
word_3 <- rep(c("thanks","", "", "comments", "par",""),1000)
word_4 <- rep(c("thanks","", "", "comments", "par",""),1000)
word_5 <- rep(c("", "one", "tricky", "one", "", "one"),1000)

使用完全相同的代码并且有效。

r：pmatch不适用于大数据帧

1 个答案: