将数据与r中的部分匹配合并 [英] merge data with partial match in r
问题描述
我有两个数据集
datf1 <- data.frame (name = c("regular", "kklmin", "notSo", "Jijoh",
"Kish", "Lissp", "Kcn", "CCCa"),
number1 = c(1, 8, 9, 2, 18, 25, 33, 8))
#-----------
name number1
1 regular 1
2 kklmin 8
3 notSo 9
4 Jijoh 2
5 Kish 18
6 Lissp 25
7 Kcn 33
8 CCCa 8
datf2 <- data.frame (name = c("reGulr", "ntSo", "Jijoh", "sean", "LiSsp",
"KcN", "CaPN"),
number2 = c(2, 8, 12, 13, 20, 18, 13))
#-------------
name number2
1 reGulr 2
2 ntSo 8
3 Jijoh 12
4 sean 13
5 LiSsp 20
6 KcN 18
7 CaPN 13
我想按名称列合并它们,但是允许部分匹配(以避免妨碍合并大型数据集中的拼写错误,甚至检测此类拼写错误),例如
I want to merge them by name column, however with partial match is allowed (to avoid hampering merging spelling errors in large data set and even to detect such spelling errors) and for example
(1) 如果在任意位置连续四个字母(如果字母数小于 4 则全部) - 匹配即可
(1) If consecutive four letters (all if the number of letters are less than 4) at any position - match that is fine
ABBCD = BBCDK = aBBCD = ramABBBCD = ABB
(2) 匹配中不区分大小写例如 ABBCD = aBbCd
(2) Case sensitivity is off in the match e.g ABBCD = aBbCd
(3) 新数据集将保留两个名称(来自 datf1 和 datf2 的名称).这样我们就可以检测该字母是否匹配(可以单独一列显示匹配多少个字母)
(3) The new dataset will have both names (names from datf1 and datf2) preserved. So that letter we can detect if the match is perfect (may a separate column with how many letter do match)
这样的合并可能吗?
datf1 <- data.frame (name = c("xxregular", "kklmin", "notSo", "Jijoh",
"Kish", "Lissp", "Kcn", "CCCa"),
number1 = c(1, 8, 9, 2, 18, 25, 33, 8))
datf2 <- data.frame (name = c("reGulr", "ntSo", "Jijoh", "sean",
"LiSsp", "KcN", "CaPN"),
number2 = c(2, 8, 12, 13, 20, 18, 13))
uglyMerge(datf1, datf2)
name1 name2 number1 number2 matches
1 xxregular <NA> 1 NA 0
2 kklmin <NA> 8 NA 0
3 notSo <NA> 9 NA 0
4 Jijoh Jijoh 2 12 5
5 Kish <NA> 18 NA 0
6 Lissp LiSsp 25 20 5
7 Kcn KcN 33 18 3
8 CCCa <NA> 8 NA 0
9 <NA> reGulr NA 2 0
10 <NA> ntSo NA 8 0
11 <NA> sean NA 13 0
12 <NA> CaPN NA 13 0
推荐答案
也许有一个简单的解决方案,但我找不到.
恕我直言,您必须自己实现这种合并.
请在下面找到一个丑陋的例子(有很大的改进空间):
Maybe there is a simple solution but I can't find any.
IMHO you have to implement this kind of merging for your own.
Please find an ugly example below (there is a lot of space for improvements):
uglyMerge <- function(df1, df2) {
## lower all strings to allow case-insensitive comparison
lowerNames1 <- tolower(df1[, 1]);
lowerNames2 <- tolower(df2[, 1]);
## split strings into single characters
names1 <- strsplit(lowerNames1, "");
names2 <- strsplit(lowerNames2, "");
## create the final dataframe
mergedDf <- data.frame(name1=as.character(df1[,1]), name2=NA,
number1=df1[,2], number2=NA, matches=0,
stringsAsFactors=FALSE);
## store names of dataframe2 (to remember which strings have no match)
toMerge <- df2[, 1];
for (i in seq(along=names1)) {
for (j in seq(along=names2)) {
## set minimal match to 4 or to string length
minMatch <- min(4, length(names2[[j]]));
## find single matches
matches <- names1[[i]] %in% names2[[j]];
## look for consecutive matches
r <- rle(matches);
## any matches found?
if (any(r$values)) {
## find max consecutive match
possibleMatch <- r$value == TRUE;
maxPos <- which(which.max(r$length[possibleMatch]) & possibleMatch)[1];
## store max conscutive match length
maxMatch <- r$length[maxPos];
## to remove FALSE-POSITIVES (e.g. CCC and kcn) find
## largest substring
start <- sum(r$length[0:(maxPos-1)]) + 1;
stop <- start + r$length[maxPos] - 1;
maxSubStr <- substr(lowerNames1[i], start, stop);
## all matching criteria fulfilled
isConsecutiveMatch <- maxMatch >= minMatch &&
grepl(pattern=maxSubStr, x=lowerNames2[j], fixed=TRUE) &&
nchar(maxSubStr) > 0;
if (isConsecutiveMatch) {
## merging
mergedDf[i, "matches"] <- maxMatch
mergedDf[i, "name2"] <- as.character(df2[j, 1]);
mergedDf[i, "number2"] <- df2[j, 2];
## don't append this row to mergedDf because already merged
toMerge[j] <- NA;
## stop inner for loop here to avoid possible second match
break;
}
}
}
}
## append not matched rows to mergedDf
toMerge <- which(df2[, 1] == toMerge);
df2 <- data.frame(name1=NA, name2=as.character(df2[toMerge, 1]),
number1=NA, number2=df2[toMerge, 2], matches=0,
stringsAsFactors=FALSE);
mergedDf <- rbind(mergedDf, df2);
return (mergedDf);
}
输出:
> uglyMerge(datf1, datf2)
name1 name2 number1 number2 matches
1 xxregular reGulr 1 2 5
2 kklmin <NA> 8 NA 0
3 notSo <NA> 9 NA 0
4 Jijoh Jijoh 2 12 5
5 Kish <NA> 18 NA 0
6 Lissp LiSsp 25 20 5
7 Kcn KcN 33 18 3
8 CCCa <NA> 8 NA 0
9 <NA> ntSo NA 8 0
10 <NA> sean NA 13 0
11 <NA> CaPN NA 13 0
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