10  10. tibbles and tribbles

10.1 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")

10.2 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:

10.2.1 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    

10.2.2 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

10.3 Key Differences from data.frames

Tibbles have several important differences from traditional data.frames:

10.3.1 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      2024-01-19    22         71                111
 2 P0002      2024-01-21    80         61                136
 3 P0003      2024-01-29    24         74                130
 4 P0004      2024-01-12    58         81                144
 5 P0005      2024-01-10    55         74                115
 6 P0006      2024-01-08    39         63                140
 7 P0007      2024-01-06    39         75                152
 8 P0008      2024-01-26    80         71                121
 9 P0009      2024-01-23    30         68                121
10 P0010      2024-01-19    59         60                110
# 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 2024-01-19  22         71                111
2       P0002 2024-01-21  80         61                136
3       P0003 2024-01-29  24         74                130
4       P0004 2024-01-12  58         81                144
5       P0005 2024-01-10  55         74                115
6       P0006 2024-01-08  39         63                140
7       P0007 2024-01-06  39         75                152
8       P0008 2024-01-26  80         71                121
9       P0009 2024-01-23  30         68                121
10      P0010 2024-01-19  59         60                110
11      P0011 2024-01-06  26         76                140
12      P0012 2024-01-02  59         73                109
13      P0013 2024-01-02  36         70                105
14      P0014 2024-01-29  39         73                115
15      P0015 2024-01-02  71         78                117
16      P0016 2024-01-26  39         93                127
17      P0017 2024-01-13  67         81                131
18      P0018 2024-01-23  89         70                110
19      P0019 2024-01-02  73         84                132
20      P0020 2024-01-08  32         69                159
21      P0021 2024-01-28  44         62                120
22      P0022 2024-01-07  88         77                112
23      P0023 2024-01-02  90         92                100
24      P0024 2024-01-18  93         76                112
25      P0025 2024-01-21  52         87                121
   blood_pressure_dia temperature oxygen_saturation
1                  72        98.6                99
2                  94        97.4                96
3                  75        98.4                95
4                 108        97.8                98
5                  69        99.2                95
6                  82        99.3                97
7                  60       100.2                99
8                  91        98.5                98
9                  86        98.9                97
10                 67        98.2                99
11                 91        98.8                97
12                 81        98.7               101
13                 78        99.2                98
14                 87        98.4                97
15                 81        98.7                99
16                 72        98.2                94
17                 78        98.6                96
18                 68        98.3                97
19                 73        97.8                99
20                 69        98.9                99
21                101        98.2               100
22                 74        98.4                97
23                 72        98.9               101
24                 71        98.8                97
25                 70        98.7               100
   cholesterol glucose weight_kg height_cm
1          214     114      87.1       175
2          200     130      58.6       173
3          243      97      63.7       165
4          151     125      64.5       172
5          188     128      89.3       184
6          186     101      67.1       167
7          151      85      76.4       135
8          243      75      51.5       177
9          137      97      65.3       146
10         227      75      64.5       159
11         230      87      71.7       177
12         141     117      46.3       168
13         178     111      68.3       165
14         150     102      56.9       173
15         204     101      74.1       173
16         163      99      86.6       165
17         173     109      52.7       174
18         226      83      54.5       174
19         185     103      61.6       168
20         203      72      40.5       162
21         181      98     104.1       172
22         191     119      76.1       188
23         203     106      65.8       147
24         196     101      75.3       169
25         213     116      51.4       163

10.4 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      2024-01-19    22         71                111
 2 P0002      2024-01-21    80         61                136
 3 P0003      2024-01-29    24         74                130
 4 P0004      2024-01-12    58         81                144
 5 P0005      2024-01-10    55         74                115
 6 P0006      2024-01-08    39         63                140
 7 P0007      2024-01-06    39         75                152
 8 P0008      2024-01-26    80         71                121
 9 P0009      2024-01-23    30         68                121
10 P0010      2024-01-19    59         60                110
11 P0011      2024-01-06    26         76                140
12 P0012      2024-01-02    59         73                109
13 P0013      2024-01-02    36         70                105
14 P0014      2024-01-29    39         73                115
15 P0015      2024-01-02    71         78                117
16 P0016      2024-01-26    39         93                127
17 P0017      2024-01-13    67         81                131
18 P0018      2024-01-23    89         70                110
19 P0019      2024-01-02    73         84                132
20 P0020      2024-01-08    32         69                159
# 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      2024-01-19    22         71                111
 2 P0002      2024-01-21    80         61                136
 3 P0003      2024-01-29    24         74                130
 4 P0004      2024-01-12    58         81                144
 5 P0005      2024-01-10    55         74                115
 6 P0006      2024-01-08    39         63                140
 7 P0007      2024-01-06    39         75                152
 8 P0008      2024-01-26    80         71                121
 9 P0009      2024-01-23    30         68                121
10 P0010      2024-01-19    59         60                110
11 P0011      2024-01-06    26         76                140
12 P0012      2024-01-02    59         73                109
13 P0013      2024-01-02    36         70                105
14 P0014      2024-01-29    39         73                115
15 P0015      2024-01-02    71         78                117
16 P0016      2024-01-26    39         93                127
17 P0017      2024-01-13    67         81                131
18 P0018      2024-01-23    89         70                110
19 P0019      2024-01-02    73         84                132
20 P0020      2024-01-08    32         69                159
21 P0021      2024-01-28    44         62                120
22 P0022      2024-01-07    88         77                112
23 P0023      2024-01-02    90         92                100
24 P0024      2024-01-18    93         76                112
25 P0025      2024-01-21    52         87                121
# ℹ 7 more variables: blood_pressure_dia <dbl>,
#   temperature <dbl>, oxygen_saturation <dbl>,
#   cholesterol <dbl>, glucose <dbl>, weight_kg <dbl>,
#   height_cm <dbl>

10.4.1 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      2024-01-19    22         71                111
 2 P0002      2024-01-21    80         61                136
 3 P0003      2024-01-29    24         74                130
 4 P0004      2024-01-12    58         81                144
 5 P0005      2024-01-10    55         74                115
 6 P0006      2024-01-08    39         63                140
 7 P0007      2024-01-06    39         75                152
 8 P0008      2024-01-26    80         71                121
 9 P0009      2024-01-23    30         68                121
10 P0010      2024-01-19    59         60                110
# 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      2024-01-19    22         71                111                 72        98.6                99         214     114      87.1       175
 2 P0002      2024-01-21    80         61                136                 94        97.4                96         200     130      58.6       173
 3 P0003      2024-01-29    24         74                130                 75        98.4                95         243      97      63.7       165
 4 P0004      2024-01-12    58         81                144                108        97.8                98         151     125      64.5       172
 5 P0005      2024-01-10    55         74                115                 69        99.2                95         188     128      89.3       184
 6 P0006      2024-01-08    39         63                140                 82        99.3                97         186     101      67.1       167
 7 P0007      2024-01-06    39         75                152                 60       100.                 99         151      85      76.4       135
 8 P0008      2024-01-26    80         71                121                 91        98.5                98         243      75      51.5       177
 9 P0009      2024-01-23    30         68                121                 86        98.9                97         137      97      65.3       146
10 P0010      2024-01-19    59         60                110                 67        98.2                99         227      75      64.5       159
# ℹ 15 more rows

10.4.2 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    

10.5 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    

10.6 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

10.7 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"

10.8 Other differences between tibbles and dataframes

10.8.1 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