How to create a data frame column with letters of both size in R?

To create a data frame column with letters of both sizes, we can simply use the letters function and LETTERS function, the first one corresponds to lowercase letters and the latter corresponds to uppercase letters with single square brackets as shown in the below examples.

Example1

df1<-data.frame(UPPER=LETTERS[1:26])
df1

Output

  UPPER
1  A
2  B
3  C
4  D
5  E
6  F
7  G
8  H
9  I
10 J
11 K
12 L
13 M
14 N
15 O
16 P
17 Q
18 R
19 S
20 T
21 U
22 V
23 W
24 X
25 Y
26 Z

Example2

df2<-data.frame(lower=letters[1:26])
df2

Output

  lower
1  a
2  b
3  c
4  d
5  e
6  f
7  g
8  h
9  i
10 j
11 k
12 l
13 m
14 n
15 o
16 p
17 q
18 r
19 s
20 t
21 u
22 v
23 w
24 x
25 y
26 z