9  9. tibbles and tribbles

9.1 Introduction to Tibbles

# Tibbles are part of the tibble package, which is included in tidyverse
# You can install/load tibble directly
if(!require(tibble)) {install.packages("tibble");require(tibble);}
Loading required package: tibble
# For more info see:
#
# help(package="tibble")

9.2 What are Tibbles?

Tibbles are a modern reimagining of R’s traditional data.frame. They are designed to make working with data frames easier and more consistent. Here’s how to create a basic tibble:

9.2.1 tibble() function is similar to data.frame() function

Create a tibble with the tibble function. It’s use is very similar to how you would use the data.frame function to create a dataframe (we’re assuming that you’re familiar with creating dataframes in R)

# Create a tibble directly
my_tibble = tibble(
  x = 1:3,
  y = letters[1:3],
  z = LETTERS[1:3]
)
my_tibble
# A tibble: 3 × 3
      x y     z    
  <int> <chr> <chr>
1     1 a     A    
2     2 b     B    
3     3 c     C    

9.2.2 as_tibble() to convert data.frame or matrix to a tibble

# convert a dataframe to a tibble

df = data.frame(
  numbers = 1:3,
  letters = c("a", "b", "c")
)

tbl = as_tibble(df)
tbl

# convert a matrix to a tibble

mat = matrix(seq(10,120,by=10), nrow=3,ncol = 4) 
tbl = as_tibble(mat)
tbl

9.3 Key Differences from data.frames

Tibbles have several important differences from traditional data.frames:

9.3.1 Default Printing Behavior

# Create a wide tibble with many columns 25 rows.

health_data = tibble(
  patient_id = sprintf("P%04d", 1:25),
  admit_date = as.Date("2024-01-01") + sample(0:30, 25, replace = TRUE),
  age = sample(18:95, 25, replace = TRUE),
  heart_rate = round(rnorm(25, 75, 10)),
  blood_pressure_sys = round(rnorm(25, 120, 15)),
  blood_pressure_dia = round(rnorm(25, 80, 10)),
  temperature = round(rnorm(25, 98.6, 0.5), 1),
  oxygen_saturation = round(rnorm(25, 98, 2)),
  cholesterol = round(rnorm(25, 190, 30)),
  glucose = round(rnorm(25, 100, 20)),
  weight_kg = round(rnorm(25, 70, 15), 1),
  height_cm = round(rnorm(25, 170, 10))
)

# Tibbles show only the first 10 rows by default
# and only columns that fit on screen
health_data
# A tibble: 25 × 12
   patient_id admit_date   age heart_rate blood_pressure_sys
   <chr>      <date>     <int>      <dbl>              <dbl>
 1 P0001      2024-01-05    69         61                106
 2 P0002      2024-01-01    72         69                125
 3 P0003      2024-01-10    89         62                132
 4 P0004      2024-01-20    75         53                120
 5 P0005      2024-01-25    22         79                134
 6 P0006      2024-01-12    73         80                132
 7 P0007      2024-01-31    39         79                114
 8 P0008      2024-01-27    22         75                123
 9 P0009      2024-01-11    54         81                124
10 P0010      2024-01-05    52         90                130
# ℹ 15 more rows
# ℹ 7 more variables: blood_pressure_dia <dbl>,
#   temperature <dbl>, oxygen_saturation <dbl>,
#   cholesterol <dbl>, glucose <dbl>, weight_kg <dbl>,
#   height_cm <dbl>
# Compare to data.frame which tries to print everything
as.data.frame(health_data)
   patient_id admit_date age heart_rate blood_pressure_sys
1       P0001 2024-01-05  69         61                106
2       P0002 2024-01-01  72         69                125
3       P0003 2024-01-10  89         62                132
4       P0004 2024-01-20  75         53                120
5       P0005 2024-01-25  22         79                134
6       P0006 2024-01-12  73         80                132
7       P0007 2024-01-31  39         79                114
8       P0008 2024-01-27  22         75                123
9       P0009 2024-01-11  54         81                124
10      P0010 2024-01-05  52         90                130
11      P0011 2024-01-04  64         82                124
12      P0012 2024-01-18  93         76                 86
13      P0013 2024-01-01  58         77                120
14      P0014 2024-01-12  78         76                126
15      P0015 2024-01-17  23         69                128
16      P0016 2024-01-09  43         69                103
17      P0017 2024-01-17  86         70                114
18      P0018 2024-01-17  62         52                138
19      P0019 2024-01-09  36         79                127
20      P0020 2024-01-14  34         74                149
21      P0021 2024-01-07  79         71                101
22      P0022 2024-01-19  53         81                104
23      P0023 2024-01-03  81         69                100
24      P0024 2024-01-02  30         77                141
25      P0025 2024-01-19  81         65                153
   blood_pressure_dia temperature oxygen_saturation
1                  70        99.3                98
2                  75        98.1               100
3                  75        99.0                98
4                  71        98.0                97
5                  76        98.6                99
6                  92        99.5               100
7                  71        98.8               101
8                  85        99.2                99
9                  66        99.6               101
10                 80        99.0                98
11                 55        97.3                99
12                 84        98.6                99
13                 84        99.1               102
14                 74        98.2               102
15                 90        98.8                97
16                 78        98.8               100
17                 74        98.5                95
18                 59        99.1               100
19                 83        98.9                93
20                 98        98.4               103
21                 79        97.5               100
22                 73        99.0                96
23                 76        98.1                98
24                 75        98.8               100
25                 71        99.1                97
   cholesterol glucose weight_kg height_cm
1          178     109      76.9       168
2          180      79      54.9       182
3          202     113      53.9       189
4          125      79     104.1       190
5          142     122      73.7       163
6          149      80      54.7       157
7          176     100      69.9       156
8          178      77      87.1       158
9          222      83      78.0       162
10         233     107      65.4       178
11         192     101      70.7       158
12         121     113      67.6       140
13         219     128      71.8       163
14         198     104      43.9       193
15         168      91      52.2       164
16         234      97      48.0       176
17         164     110      96.2       167
18         164     106     108.4       171
19         169      70      62.3       175
20         165     138      76.1       168
21         218     111      64.0       169
22         245      83      54.1       173
23         183     131      49.0       168
24         183      68      69.3       163
25         174     119      61.5       162

9.4 Printing More Rows/Columns of a Tibble

# By default, print() shows 10 rows. Use n= to show more rows
print(health_data, n = 20)  # Shows 20 rows
# A tibble: 25 × 12
   patient_id admit_date   age heart_rate blood_pressure_sys
   <chr>      <date>     <int>      <dbl>              <dbl>
 1 P0001      2024-01-05    69         61                106
 2 P0002      2024-01-01    72         69                125
 3 P0003      2024-01-10    89         62                132
 4 P0004      2024-01-20    75         53                120
 5 P0005      2024-01-25    22         79                134
 6 P0006      2024-01-12    73         80                132
 7 P0007      2024-01-31    39         79                114
 8 P0008      2024-01-27    22         75                123
 9 P0009      2024-01-11    54         81                124
10 P0010      2024-01-05    52         90                130
11 P0011      2024-01-04    64         82                124
12 P0012      2024-01-18    93         76                 86
13 P0013      2024-01-01    58         77                120
14 P0014      2024-01-12    78         76                126
15 P0015      2024-01-17    23         69                128
16 P0016      2024-01-09    43         69                103
17 P0017      2024-01-17    86         70                114
18 P0018      2024-01-17    62         52                138
19 P0019      2024-01-09    36         79                127
20 P0020      2024-01-14    34         74                149
# ℹ 5 more rows
# ℹ 7 more variables: blood_pressure_dia <dbl>,
#   temperature <dbl>, oxygen_saturation <dbl>,
#   cholesterol <dbl>, glucose <dbl>, weight_kg <dbl>,
#   height_cm <dbl>
# To see all rows
print(health_data, n = Inf)
# A tibble: 25 × 12
   patient_id admit_date   age heart_rate blood_pressure_sys
   <chr>      <date>     <int>      <dbl>              <dbl>
 1 P0001      2024-01-05    69         61                106
 2 P0002      2024-01-01    72         69                125
 3 P0003      2024-01-10    89         62                132
 4 P0004      2024-01-20    75         53                120
 5 P0005      2024-01-25    22         79                134
 6 P0006      2024-01-12    73         80                132
 7 P0007      2024-01-31    39         79                114
 8 P0008      2024-01-27    22         75                123
 9 P0009      2024-01-11    54         81                124
10 P0010      2024-01-05    52         90                130
11 P0011      2024-01-04    64         82                124
12 P0012      2024-01-18    93         76                 86
13 P0013      2024-01-01    58         77                120
14 P0014      2024-01-12    78         76                126
15 P0015      2024-01-17    23         69                128
16 P0016      2024-01-09    43         69                103
17 P0017      2024-01-17    86         70                114
18 P0018      2024-01-17    62         52                138
19 P0019      2024-01-09    36         79                127
20 P0020      2024-01-14    34         74                149
21 P0021      2024-01-07    79         71                101
22 P0022      2024-01-19    53         81                104
23 P0023      2024-01-03    81         69                100
24 P0024      2024-01-02    30         77                141
25 P0025      2024-01-19    81         65                153
# ℹ 7 more variables: blood_pressure_dia <dbl>,
#   temperature <dbl>, oxygen_saturation <dbl>,
#   cholesterol <dbl>, glucose <dbl>, weight_kg <dbl>,
#   height_cm <dbl>

9.4.1 Controlling Column Width

# width argument to print specifies the number of characters that should
# be printed in the widest row. In effect, this limits the number of columns
# being output to those columns that fit in the specified width.
print(health_data, width = 75)
# A tibble: 25 × 12
   patient_id admit_date   age heart_rate blood_pressure_sys
   <chr>      <date>     <int>      <dbl>              <dbl>
 1 P0001      2024-01-05    69         61                106
 2 P0002      2024-01-01    72         69                125
 3 P0003      2024-01-10    89         62                132
 4 P0004      2024-01-20    75         53                120
 5 P0005      2024-01-25    22         79                134
 6 P0006      2024-01-12    73         80                132
 7 P0007      2024-01-31    39         79                114
 8 P0008      2024-01-27    22         75                123
 9 P0009      2024-01-11    54         81                124
10 P0010      2024-01-05    52         90                130
# ℹ 15 more rows
# ℹ 7 more variables: blood_pressure_dia <dbl>, temperature <dbl>,
#   oxygen_saturation <dbl>, cholesterol <dbl>, glucose <dbl>,
#   weight_kg <dbl>, height_cm <dbl>
# Show all columns by setting width to Inf
print(health_data, width = Inf)
# A tibble: 25 × 12
   patient_id admit_date   age heart_rate blood_pressure_sys blood_pressure_dia temperature oxygen_saturation cholesterol glucose weight_kg height_cm
   <chr>      <date>     <int>      <dbl>              <dbl>              <dbl>       <dbl>             <dbl>       <dbl>   <dbl>     <dbl>     <dbl>
 1 P0001      2024-01-05    69         61                106                 70        99.3                98         178     109      76.9       168
 2 P0002      2024-01-01    72         69                125                 75        98.1               100         180      79      54.9       182
 3 P0003      2024-01-10    89         62                132                 75        99                  98         202     113      53.9       189
 4 P0004      2024-01-20    75         53                120                 71        98                  97         125      79     104.        190
 5 P0005      2024-01-25    22         79                134                 76        98.6                99         142     122      73.7       163
 6 P0006      2024-01-12    73         80                132                 92        99.5               100         149      80      54.7       157
 7 P0007      2024-01-31    39         79                114                 71        98.8               101         176     100      69.9       156
 8 P0008      2024-01-27    22         75                123                 85        99.2                99         178      77      87.1       158
 9 P0009      2024-01-11    54         81                124                 66        99.6               101         222      83      78         162
10 P0010      2024-01-05    52         90                130                 80        99                  98         233     107      65.4       178
# ℹ 15 more rows

9.4.2 Row Names

# data.frames can have row names
df_rownames = data.frame(
  x = 1:3,
  y = letters[1:3],
  row.names = c("row1", "row2", "row3")
)
df_rownames
     x y
row1 1 a
row2 2 b
row3 3 c
# Tibbles don't support row names
# If you convert a data.frame with row names to a tibble,
# the row names become a regular column called 'rowname'
as_tibble(df_rownames, rownames = "id")
# A tibble: 3 × 3
  id        x y    
  <chr> <int> <chr>
1 row1      1 a    
2 row2      2 b    
3 row3      3 c    

9.5 Creating Tibbles

You can create tibbles in several ways:

# Using tibble()
t1 = tibble(
  x = 1:5,
  y = x * 2,  # Note: you can refer to columns created earlier
  z = letters[1:5]
)
t1
# A tibble: 5 × 3
      x     y z    
  <int> <dbl> <chr>
1     1     2 a    
2     2     4 b    
3     3     6 c    
4     4     8 d    
5     5    10 e    

9.6 creating tibble row by row using tribbles

While reading the raw code for creating a dataframe or a tibble, it can be challenging to visualize what the actual dataframe/tibble will look like. This is because when typing the data into the code, each column is typed horrizontally instead of vertically. For example:

# Using tribble() for transposed input
# Useful for small, manual data entry
stuff = tribble(
  col1 = c("a",  "b",   "c"),
  col2 = c( 1,    2,     3)
  col3 = c(TRUE, FALSE, TRUE))

# The code above lays out columns horizontally. 
# The actual dataframe displays columns vertically.
stuff

A “tribble” (i.e. TRansposed tIBBLE) is just a different way of typing the code that becomes a tibble. Each column heading is prefixed with a tilde (~). The columns can be laid out vertically in the code, making the code much more readable. See the example below.

# Using tribble() for transposed input
# Useful for small, manual data entry
stuff = tribble(
  ~col1, ~col2, ~col3,
  "a",   1,     TRUE,
  "b",   2,     FALSE,
  "c",   3,     TRUE
)

# The following looks much more similar to the code that created it.
stuff

9.7 Converting Between Tibbles and data.frames

# Convert data.frame to tibble
df = data.frame(
  x = 1:3,
  y = letters[1:3]
)
tbl = as_tibble(df)

# Convert tibble back to data.frame
df_again = as.data.frame(tbl)

# Check classes
class(tbl)
[1] "tbl_df"     "tbl"        "data.frame"
class(df_again)
[1] "data.frame"

9.8 Other differences between tibbles and dataframes

9.8.1 Variable Names and Subsetting

# data.frames modify non-syntactic names
df_names = data.frame(
  `1` = 1:3,
  `2+2` = 4:6,
  check.names = TRUE  # default behavior
)
names(df_names)  # Names are modified
[1] "X1"   "X2.2"
# Tibbles preserve original names
tbl_names = tibble(
  `1` = 1:3,
  `2+2` = 4:6
)
names(tbl_names)  # Original names kept
[1] "1"   "2+2"
# Subsetting differences
# data.frame allows partial matching of variable names
df = data.frame(numbers = 1:3, letters = c("a", "b", "c"))
df$num  # Partial matching works
[1] 1 2 3
# Tibbles require exact matching
tbl = tibble(numbers = 1:3, letters = c("a", "b", "c"))
try(tbl$num)  # This will raise an error
Warning: Unknown or uninitialised column: `num`.
NULL