R - Concatenate two dataframes

Question

Given two dataframes a and b    gt  a            a           b           c 1 -0 2246894 -1 48167912 -1 65099363 2  0 5559320 -0 87898575 -0 15634590 3  1 8469466 -0 01487524 -0 53098215 4 -0 6875051  0 23880967  0 01824621 5 -0 6735163  0 75485292  0 44154092    gt  b            a          c 1  0 4287284 -0 3295925 2  0 5201492  0 3341251 3 -2 6355570  1 7916780 4 -1 3645337  1 3642276 5 -0 4954542 -0 6660001   Is there a simple way to concatenate these so as to return a new data frame of the form below    gt  new            a                   b           c 1  -0 2246894   -1 48167912106676 -1 65099363 2   0 5559320  -0 878985746842256 -0 15634590 3   1 8469466 -0 0148752354840942 -0 53098215 4  -0 6875051   0 238809666690982  0 01824621 5  -0 6735163   0 754852923524198  0 44154092 6   0 4287284                  NA -0 32959248 7   0 5201492                  NA  0 33412510 8  -2 6355570                  NA  1 79167801 9  -1 3645337                  NA  1 36422764 10 -0 4954542                  NA -0 66600006   I want to merge the dataframes  match the headers and insert NA in for positions in dataframe b where the header is missing

User · Answer

you can use the function   bind rows a b   from the dplyr library

User · Answer

Here s a simple little function that will rbind two datasets together after auto-detecting what columns are missing from each and adding them with all NAs   For whatever reason this returns MUCH faster on larger datasets than using the merge function   fastmerge  lt - function d1  d2      d1 names  lt - names d1    d2 names  lt - names d2       columns in d1 but not in d2   d2 add  lt - setdiff d1 names  d2 names       columns in d2 but not in d1   d1 add  lt - setdiff d2 names  d1 names       add blank columns to d2   if length d2 add   gt  0        for i in 1 length d2 add           d2 d2 add i    lt - NA                add blank columns to d1   if length d1 add   gt  0        for i in 1 length d1 add           d1 d1 add i    lt - NA              return rbind d1  d2

User · Answer

You want  rbind    b b  lt - NA new  lt - rbind a  b    rbind requires the data frames to have the same columns   The first line adds column b to data frame b   Results   gt  a  lt - data frame a c 0 1 2   b c 3 4 5   c c 6 7 8    gt  a   a b c 1 0 3 6 2 1 4 7 3 2 5 8  gt  b  lt - data frame a c 9 10 11   c c 12 13 14    gt  b    a  c 1  9 12 2 10 13 3 11 14  gt  b b  lt - NA  gt  b    a  c  b 1  9 12 NA 2 10 13 NA 3 11 14 NA  gt  new  lt - rbind a b   gt  new    a  b  c 1  0  3  6 2  1  4  7 3  2  5  8 4  9 NA 12 5 10 NA 13 6 11 NA 14

User · Answer

You may use rbind but in this case you need to have the same number of columns in both tables  so try the following   b b lt -as double NA   keeping numeric format is essential for further calculations new lt -rbind a b

User · Answer

Try the plyr package   rbind fill a b c

[r] R - Concatenate two dataframes?

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