carats <- pull(diamonds %>% distinct(carat) %>% arrange(carat))

get_price_by_category <- function(dataset, x, y) {
    print(c(x, typeof(x)))
    dataset %>% filter(carat == x) %>% print()
}

carats %>% walk(get_price_by_category, dataset = diamonds, y= "price")

[1] "0.2"    "double"
# A tibble: 0 x 10
# … with 10 variables: carat <dbl>, cut <ord>, color <ord>, clarity <ord>,
#   depth <dbl>, table <dbl>, price <int>, x <dbl>, y <dbl>, z <dbl>
[1] "0.21"   "double"
# A tibble: 0 x 10
# … with 10 variables: carat <dbl>, cut <ord>, color <ord>, clarity <ord>,
#   depth <dbl>, table <dbl>, price <int>, x <dbl>, y <dbl>, z <dbl>
[1] "0.22"   "double"
# A tibble: 0 x 10
# … with 10 variables: carat <dbl>, cut <ord>, color <ord>, clarity <ord>,
#   depth <dbl>, table <dbl>, price <int>, x <dbl>, y <dbl>, z <dbl>
[1] "0.23"   "double"
# A tibble: 0 x 10
# … with 10 variables: carat <dbl>, cut <ord>, color <ord>, clarity <ord>,
#   depth <dbl>, table <dbl>, price <int>, x <dbl>, y <dbl>, z <dbl>
...

carats <- pull(diamonds %>% distinct(carat) %>% arrange(carat))

get_price_by_category <- function(dataset, x, y) {
    print(c(x, typeof(x)))
    dataset %>% filter(carat == x) %>% print()
}

for (c in carats) {
    get_price_by_category(diamonds, c, y= "price")
}

carats <- pull(diamonds %>% distinct(carat) %>% arrange(carat))

get_price_by_category <- function(dataset, x, y) {
    print(c(c, typeof(c)))
    dataset %>% filter(carat == c) %>% print()
}

for (c in carats) {
    get_price_by_category(diamonds, c, y= "price")
}

[1] "0.2"    "double"
# A tibble: 12 x 10
   carat cut       color clarity depth table price     x     y     z
   <dbl> <ord>     <ord> <ord>   <dbl> <dbl> <int> <dbl> <dbl> <dbl>
 1   0.2 Premium   E     SI2      60.2    62   345  3.79  3.75  2.27
 2   0.2 Premium   E     VS2      59.8    62   367  3.79  3.77  2.26
 3   0.2 Premium   E     VS2      59      60   367  3.81  3.78  2.24
 4   0.2 Premium   E     VS2      61.1    59   367  3.81  3.78  2.32
 5   0.2 Premium   E     VS2      59.7    62   367  3.84  3.8   2.28
 6   0.2 Ideal     E     VS2      59.7    55   367  3.86  3.84  2.3
 7   0.2 Premium   F     VS2      62.6    59   367  3.73  3.71  2.33
 8   0.2 Ideal     D     VS2      61.5    57   367  3.81  3.77  2.33
 9   0.2 Very Good E     VS2      63.4    59   367  3.74  3.71  2.36
10   0.2 Ideal     E     VS2      62.2    57   367  3.76  3.73  2.33
11   0.2 Premium   D     VS2      62.3    60   367  3.73  3.68  2.31
12   0.2 Premium   D     VS2      61.7    60   367  3.77  3.72  2.31
[1] "0.21"   "double"
# A tibble: 9 x 10
  carat cut       color clarity depth table price     x     y     z
  <dbl> <ord>     <ord> <ord>   <dbl> <dbl> <int> <dbl> <dbl> <dbl>
1  0.21 Premium   E     SI1      59.8    61   326  3.89  3.84  2.31
2  0.21 Very Good E     VS2      63.2    54   386  3.82  3.78  2.4
3  0.21 Premium   E     VS2      60.5    59   386  3.87  3.83  2.33
4  0.21 Premium   E     VS2      59.6    56   386  3.93  3.89  2.33
5  0.21 Premium   D     VS2      61.6    59   386  3.82  3.78  2.34
6  0.21 Premium   D     VS2      60.6    60   386  3.85  3.81  2.32
7  0.21 Premium   D     VS2      59.1    62   386  3.89  3.86  2.29
8  0.21 Premium   D     VS2      58.3    59   386  3.96  3.93  2.3
9  0.21 Premium   E     SI2      61.9    56   394  3.84  3.82  2.37
...