13  13. tibbles and tribbles

13.1 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")

13.2 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:

13.2.1 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    

13.2.2 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

13.3 Key Differences from data.frames

Tibbles have several important differences from traditional data.frames:

13.3.1 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      2024-01-23    20         82                133
 2 P0002      2024-01-31    35         81                132
 3 P0003      2024-01-06    34         64                117
 4 P0004      2024-01-09    77         81                133
 5 P0005      2024-01-06    74         46                109
 6 P0006      2024-01-23    71         64                118
 7 P0007      2024-01-25    87         69                118
 8 P0008      2024-01-08    91         71                126
 9 P0009      2024-01-23    32         60                108
10 P0010      2024-01-30    65         63                100
# 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 2024-01-23  20         82                133
2       P0002 2024-01-31  35         81                132
3       P0003 2024-01-06  34         64                117
4       P0004 2024-01-09  77         81                133
5       P0005 2024-01-06  74         46                109
6       P0006 2024-01-23  71         64                118
7       P0007 2024-01-25  87         69                118
8       P0008 2024-01-08  91         71                126
9       P0009 2024-01-23  32         60                108
10      P0010 2024-01-30  65         63                100
11      P0011 2024-01-02  83         85                131
12      P0012 2024-01-03  70         79                107
13      P0013 2024-01-07  74         86                139
14      P0014 2024-01-15  47         91                102
15      P0015 2024-01-17  58         82                110
16      P0016 2024-01-30  25         63                132
17      P0017 2024-01-30  71         68                134
18      P0018 2024-01-05  43         80                 89
19      P0019 2024-01-26  66         67                114
20      P0020 2024-01-19  56         71                140
21      P0021 2024-01-28  85         76                114
22      P0022 2024-01-17  43         80                109
23      P0023 2024-01-12  37         63                121
24      P0024 2024-01-08  18         78                127
25      P0025 2024-01-30  30         74                137
   blood_pressure_dia temperature oxygen_saturation
1                  69        98.3                95
2                  63        99.0               100
3                  85        97.5                96
4                  84        98.5               100
5                  79        99.2                97
6                  76        98.8                99
7                  70        98.7                96
8                  73        98.0                97
9                  78        98.6               100
10                 59        99.2                99
11                 84        98.2                96
12                 81        99.4                97
13                 97        98.8                99
14                 72        97.7                97
15                 78        98.1                95
16                 68        98.2                96
17                 85        98.4                97
18                 86        99.1                95
19                 75        98.5                97
20                 88        98.6               100
21                 77        99.5               101
22                 85        97.4                99
23                 76        99.1                98
24                 62        98.1               100
25                 78        98.5                98
   cholesterol glucose weight_kg height_cm
1          239     112      66.3       173
2          185      99      90.9       165
3          167      80      88.8       168
4          174      65      75.7       175
5          179      85      94.8       162
6          198      99      55.7       162
7          147     113      84.0       165
8          186     118      79.4       193
9          173     139      72.4       170
10         180     112      73.7       174
11         210     100      46.5       165
12         155     107      80.6       174
13         178     124      80.5       171
14         250     102      80.8       172
15         159     130      77.9       153
16         165      81      60.3       160
17         232     127      82.7       167
18         167     132      47.0       163
19         167     112      84.7       162
20         211      88      65.9       168
21         167      98      76.2       172
22         174      94      77.7       174
23         172     112      63.9       169
24         240     124      72.2       195
25         232      96      72.3       164

13.4 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      2024-01-23    20         82                133
 2 P0002      2024-01-31    35         81                132
 3 P0003      2024-01-06    34         64                117
 4 P0004      2024-01-09    77         81                133
 5 P0005      2024-01-06    74         46                109
 6 P0006      2024-01-23    71         64                118
 7 P0007      2024-01-25    87         69                118
 8 P0008      2024-01-08    91         71                126
 9 P0009      2024-01-23    32         60                108
10 P0010      2024-01-30    65         63                100
11 P0011      2024-01-02    83         85                131
12 P0012      2024-01-03    70         79                107
13 P0013      2024-01-07    74         86                139
14 P0014      2024-01-15    47         91                102
15 P0015      2024-01-17    58         82                110
16 P0016      2024-01-30    25         63                132
17 P0017      2024-01-30    71         68                134
18 P0018      2024-01-05    43         80                 89
19 P0019      2024-01-26    66         67                114
20 P0020      2024-01-19    56         71                140
# 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      2024-01-23    20         82                133
 2 P0002      2024-01-31    35         81                132
 3 P0003      2024-01-06    34         64                117
 4 P0004      2024-01-09    77         81                133
 5 P0005      2024-01-06    74         46                109
 6 P0006      2024-01-23    71         64                118
 7 P0007      2024-01-25    87         69                118
 8 P0008      2024-01-08    91         71                126
 9 P0009      2024-01-23    32         60                108
10 P0010      2024-01-30    65         63                100
11 P0011      2024-01-02    83         85                131
12 P0012      2024-01-03    70         79                107
13 P0013      2024-01-07    74         86                139
14 P0014      2024-01-15    47         91                102
15 P0015      2024-01-17    58         82                110
16 P0016      2024-01-30    25         63                132
17 P0017      2024-01-30    71         68                134
18 P0018      2024-01-05    43         80                 89
19 P0019      2024-01-26    66         67                114
20 P0020      2024-01-19    56         71                140
21 P0021      2024-01-28    85         76                114
22 P0022      2024-01-17    43         80                109
23 P0023      2024-01-12    37         63                121
24 P0024      2024-01-08    18         78                127
25 P0025      2024-01-30    30         74                137
# ℹ 7 more variables: blood_pressure_dia <dbl>,
#   temperature <dbl>, oxygen_saturation <dbl>,
#   cholesterol <dbl>, glucose <dbl>, weight_kg <dbl>,
#   height_cm <dbl>

13.4.1 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      2024-01-23    20         82                133
 2 P0002      2024-01-31    35         81                132
 3 P0003      2024-01-06    34         64                117
 4 P0004      2024-01-09    77         81                133
 5 P0005      2024-01-06    74         46                109
 6 P0006      2024-01-23    71         64                118
 7 P0007      2024-01-25    87         69                118
 8 P0008      2024-01-08    91         71                126
 9 P0009      2024-01-23    32         60                108
10 P0010      2024-01-30    65         63                100
# 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      2024-01-23    20         82                133                 69        98.3                95         239     112      66.3       173
 2 P0002      2024-01-31    35         81                132                 63        99                 100         185      99      90.9       165
 3 P0003      2024-01-06    34         64                117                 85        97.5                96         167      80      88.8       168
 4 P0004      2024-01-09    77         81                133                 84        98.5               100         174      65      75.7       175
 5 P0005      2024-01-06    74         46                109                 79        99.2                97         179      85      94.8       162
 6 P0006      2024-01-23    71         64                118                 76        98.8                99         198      99      55.7       162
 7 P0007      2024-01-25    87         69                118                 70        98.7                96         147     113      84         165
 8 P0008      2024-01-08    91         71                126                 73        98                  97         186     118      79.4       193
 9 P0009      2024-01-23    32         60                108                 78        98.6               100         173     139      72.4       170
10 P0010      2024-01-30    65         63                100                 59        99.2                99         180     112      73.7       174
# ℹ 15 more rows

13.4.2 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    

13.5 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    

13.6 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

13.7 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"

13.8 Other differences between tibbles and dataframes

13.8.1 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