Off topic:R join data frame based on the value of a column

Question

[Vincent Manzanilla]

Hi,

I would like to keep the line where the ID are the same. I know how to to it in bash nut I would like to succeed with R. I have two files with 500,000 lines and 300,000 lines.

   df1 <- data.frame(ID=c(sample(LETTERS,20,replace=FALSE)),A=sample(1:100,20,replace=FALSE),B=sample(100:1000,20,replace=FALSE))

  ID  A   B
1   F 81 337
2   J 14 400
3   B  1 620
4   L 40 326
5   T 86 315
6   D 94 797
7   U 96 309
8   Y 42 939
9   Z 18 397
10  W  8 168
11  R 71 308
12  I 83 591
13  O 67 462
14  C 63 353
15  S 88 362
16  Q 13 917
17  G 58 289
18  P 55 640
19  E  9 218
20  X 59 920

and

df2 <- data.frame(D=sample(1:100,10,replace=FALSE),E=sample(100:1000,10,replace=FALSE), ID=c(sample(LETTERS,10,replace=FALSE)))

    D   E ID
1  29 551  U
2  33 191  C
3  85 814  Q
4  55 897  D
5  46 527  V
6  57 603  T
7  45 287  K
8  79 409  Z
9  65 243  W
10 90 701  M

I would like to join the two data frames where the column ID are similar.

ID  A   B   D   E
T   86  315 57  603
D   94  797 55  897
U   96  309 29  551
Z   18  397 79  409
W   8   168 65  243
C   63  353 33  191
Q   13  917 85  814