When we want to change texts within a columns, you can have several methods which I already introduced before.

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□ How to Rename Variables within Columns in R?

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However, changing all texts and specific texts would be different. Let’s upload a data.

library(readr)

github="https://raw.githubusercontent.com/agronomy4future/raw_data_practice/main/phosphorous_data.csv"
dataA= data.frame(read_csv(url(github), show_col_types= FALSE))
dataA
            Location      ID  OM  P  pH
1          West.Hill Delta_1 4.4 30 6.0
2          West.Hill Delta_2 4.2 16 6.1
3          West.Hill Delta_3 3.6 11 6.2
4          West.Hill Delta_4 3.6 12 5.4
5          West.Hill Delta_5 4.7 15 6.3
6          West.Hill Delta_6 4.5 33 6.5
7          West.Hill Delta_7 3.7 11 6.7
8         East.Plain Delta_1 3.6 11 6.6
9         East.Plain Delta_2 2.8  6 7.1
10        East.Plain Delta_3 4.0 11 6.4
11        East.Plain Delta_4 5.8 29 7.0
12        East.Plain Delta_5 4.3 14 6.2
13        East.Plain Delta_6 4.2 14 5.8
14        East.Plain Delta_7 4.6 16 6.2
15 North.Rainshelter Delta_1 4.5 19 6.7
16 North.Rainshelter Delta_2 4.6 35 5.6
17 North.Rainshelter Delta_3 3.8 27 6.2
18 North.Rainshelter Delta_4 4.1 19 6.0
19 North.Rainshelter Delta_5 3.5 26 5.8
20 North.Rainshelter Delta_6 4.1 19 6.0
21 North.Rainshelter Delta_7 3.6 15 5.9

Now, we can change the variables name as following code:

dataA$Location[dataA$Location=="East.Plain"]="East farmland"
dataA

            Location      ID  OM  P  pH
1          West.Hill Delta_1 4.4 30 6.0
2          West.Hill Delta_2 4.2 16 6.1
3          West.Hill Delta_3 3.6 11 6.2
4          West.Hill Delta_4 3.6 12 5.4
5          West.Hill Delta_5 4.7 15 6.3
6          West.Hill Delta_6 4.5 33 6.5
7          West.Hill Delta_7 3.7 11 6.7
8      East farmland Delta_1 3.6 11 6.6
9      East farmland Delta_2 2.8  6 7.1
10     East farmland Delta_3 4.0 11 6.4
11     East farmland Delta_4 5.8 29 7.0
12     East farmland Delta_5 4.3 14 6.2
13     East farmland Delta_6 4.2 14 5.8
14     East farmland Delta_7 4.6 16 6.2
15 North.Rainshelter Delta_1 4.5 19 6.7
16 North.Rainshelter Delta_2 4.6 35 5.6
17 North.Rainshelter Delta_3 3.8 27 6.2
18 North.Rainshelter Delta_4 4.1 19 6.0
19 North.Rainshelter Delta_5 3.5 26 5.8
20 North.Rainshelter Delta_6 4.1 19 6.0
21 North.Rainshelter Delta_7 3.6 15 5.9

How about changing the text in the ID column? I want to remove ‘Delta_’ and keep only the numbers. Will you change the text one by one as follows?

dataA$ID[dataA$ID=="Delta_1"]="1"
dataA$ID[dataA$ID=="Delta_2"]="2"
dataA$ID[dataA$ID=="Delta_3"]="3"
.
.
.
dataA$ID[dataA$ID=="Delta_7"]="7"

It’s a waste of time. Here’s a simpler way.

dataA$ID=sub("Delta_","", dataA$ID)
dataA
            Location ID  OM  P  pH
1          West.Hill  1 4.4 30 6.0
2          West.Hill  2 4.2 16 6.1
3          West.Hill  3 3.6 11 6.2
4          West.Hill  4 3.6 12 5.4
5          West.Hill  5 4.7 15 6.3
6          West.Hill  6 4.5 33 6.5
7          West.Hill  7 3.7 11 6.7
8      East farmland  1 3.6 11 6.6
9      East farmland  2 2.8  6 7.1
10     East farmland  3 4.0 11 6.4
11     East farmland  4 5.8 29 7.0
12     East farmland  5 4.3 14 6.2
13     East farmland  6 4.2 14 5.8
14     East farmland  7 4.6 16 6.2
15 North.Rainshelter  1 4.5 19 6.7
16 North.Rainshelter  2 4.6 35 5.6
17 North.Rainshelter  3 3.8 27 6.2
18 North.Rainshelter  4 4.1 19 6.0
19 North.Rainshelter  5 3.5 26 5.8
20 North.Rainshelter  6 4.1 19 6.0
21 North.Rainshelter  7 3.6 15 5.9

How about changing Rainshelter to Shelter in Location column?

dataA$Location=sub("Rainshelter","shelter", dataA$Location)
dataA
        Location ID  OM  P  pH
1      West.Hill  1 4.4 30 6.0
2      West.Hill  2 4.2 16 6.1
3      West.Hill  3 3.6 11 6.2
4      West.Hill  4 3.6 12 5.4
5      West.Hill  5 4.7 15 6.3
6      West.Hill  6 4.5 33 6.5
7      West.Hill  7 3.7 11 6.7
8  East farmland  1 3.6 11 6.6
9  East farmland  2 2.8  6 7.1
10 East farmland  3 4.0 11 6.4
11 East farmland  4 5.8 29 7.0
12 East farmland  5 4.3 14 6.2
13 East farmland  6 4.2 14 5.8
14 East farmland  7 4.6 16 6.2
15 North.shelter  1 4.5 19 6.7
16 North.shelter  2 4.6 35 5.6
17 North.shelter  3 3.8 27 6.2
18 North.shelter  4 4.1 19 6.0
19 North.shelter  5 3.5 26 5.8
20 North.shelter  6 4.1 19 6.0
21 North.shelter  7 3.6 15 5.9

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