CODEWITHSUNDEEP
rmerge
user3041372
user3041372

Reputation: 31

how merge command work in r?

I have two data frame in R . first one contains some information about family and the other contains some information about all children of family the first one like:(HHchar data frame)

HHchar <- read.table(text="ID familysize
1      4
2      5
3      2
4      3",header=T)

the second one likes:(children data frame)

children <- read.table(text="ID   age   gender birthorder
1     26     1    firstchild
1     20     2    secondchild
2     20     1    firstchild 
2     18     1    firstchild
2     17     2    secondchild
2     10     1    thirdchild
3     19     1    firstchild
3     12     2    secondchild
4     10     1    firstchild",header=T)

I want this as a result:

ID    age    gender     birthorder       familysize
1     26       1        firstchild           4
1     20       2        secondchild          4
2     20       1        firstchild           5
2     18       1        secondchild          5
2     17       2        thirdchild           5
3     19       1        firstchild           4
3     12       2        secondchild          4
4     10       1        firstchild           3

For this result I use this command:

b2 <- merge (children ,HHchar,by="ID", all.x= TRUE)

I think by this command all information about people which is reported in children data frame will extracted from HHchar data frame too and b2 data frame will be build.
But something bad was happen and I see number of rows in b2 is not what I was expected.

For example:

I test this problem by small dataset but my dataset is very large (853467 rows).

So I can't test what is wrong ? Is merge command suitable for my need ?

Upvotes: 1

Views: 185

Answers (1)

so13eit
so13eit

Reputation: 952

If I understood your question correctly, this should work:

result <- merge(children, HHchar, by = "ID")

In general, the functions works as: merge(firstDF, secondDF, by.x = ColumnToJoinOnInFirstDF, by.y = ColumnToJoinOnInSecondDF)

Upvotes: 1

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