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#201–206

### Puzzles

Author: ExcelBI

All files (xlsx with puzzle and R with solution) for each and every puzzle are available on my Github. Enjoy.

### Puzzle #201

We need to find out which customer had opportunity to buy specific product (and maybe bought). We receive two tables: one presenting time of customer activity and one presenting item availability. If in second one we meet empty cell then in start column it means that it was available even before, and in finish column that it is still on stock even after last customer ends his purchasing adventure. This task looks hard, but it really not. We need to make date sequences for each person and product, than find common dates and add some transformation to get result table. Check it out.

```library(tidyverse)

path = "Power Query/PQ_Challenge_201.xlsx"
input1 = read_excel(path, range = "A2:C7")
input2 = read_excel(path, range = "A10:C16")
test = read_excel(path, range = "E1:K6")```

#### Transformation

```i1 = input1 %>%
mutate(date = map2(`Buy Date From`, `Buy Date To`, seq, by = "day")) %>%
unnest(date) %>%

i2 = input2 %>%
mutate(`Stock Start Date` = replace_na(`Stock Start Date`, min(`Stock Start Date`, na.rm = TRUE)),
`Stock Finish Date` = replace_na(`Stock Finish Date`, max(i1\$date, na.rm = TRUE))) %>%
mutate(date = map2(`Stock Start Date`, `Stock Finish Date`, seq, by = "day"))  %>%
unnest(date) %>%
select(Items, date)

result = i1 %>%
inner_join(i2, by = c("date")) %>%
pivot_wider(names_from = Items, values_from = date, values_fn = length) %>%
select(`Buyer / Items` = 1, sort(colnames(.), decreasing = FALSE)) %>%
mutate(across(-c(1), ~ifelse(is.na(.), ., "X")))```

#### Validation

```all.equal(result, test)
# [1] TRUE```

### Puzzle #202

Somebody make table that somehow represents organizational hierarchy, but like always we are assigned to clean this mess up. We need to find hierarchy level and subordinations (who reports to whom), and store it as Serial. That one was tricky to make, but let try to walk it together.

```library(tidyverse)

path = "Power Query/PQ_Challenge_202.xlsx"
input = read_excel(path, range = "A1:C18")
test  = read_excel(path, range = "E1:F18")```

#### Transformation

```result = input %>%
mutate(L1 = cumsum(!is.na(Name1))) %>%
mutate(L2 = cumsum(!is.na(Name2)), .by = L1) %>%
mutate(L3 = cumsum(!is.na(Name3)), .by = c(L1, L2)) %>%
mutate(across(starts_with("L"), ~ ifelse(. == 0, NA, .))) %>%
mutate(across(everything(), ~  as.character(.))) %>%
rowwise() %>%
mutate(Names = coalesce(Name3, Name2, Name1),
Serial = case_when(
!is.na(L3) ~ paste(L1, L2, L3, sep = "."),
!is.na(L2) ~ paste(L1,L2, sep = "."),
!is.na(L1) ~ L1
)) %>%
ungroup() %>%
select(Serial, Names)                                                                                                                                                                                                  ```

#### Validation

```identical(result, test)
# [1] TRUE```

### Puzzle #203

Messy spreadsheets, chaos in a making. How many of us have seen at least one, and fixed at least one of them. What we have today. Base of spreadsheet were 3 groups that we see in first column separated with empty rows. But there are some cells with weird strings and some numbers outside of primarely chosen rows. So we need to summarise our groups of rows (to be specific find average of each group) and get every other cells with numbers all together to category “Remaining”. We need some serious tools here.

```library(tidyverse)

path = "Power Query/PQ_Challenge_203.xlsx"
input = read_excel(path, range = "A1:C14")
test  = read_excel(path, range = "E1:F5")```

#### Transformation

```result = input %>%
mutate(Text = as.numeric(Text),
Group = consecutive_id(is.na(Amount1)) / 2 * !is.na(Amount1)) %>%
mutate(Group = ifelse(is.na(Amount1), "Remaining", paste0("Group", Group))) %>%
summarise(nmb = list(c(Amount1, Amount2, Text)), .by = Group) %>%
mutate(nmb = map(nmb, ~.x[!is.na(.x)])) %>%
mutate(avg = map_dbl(nmb, ~mean(.x, na.rm = TRUE)) %>% round()) %>%
arrange(Group) %>%
select(Group, `Avg Amount` = avg)```

There is pretty nice trick done in one of line. We are adding consective_id on column to distinguish groups, but empty rows shouldn’t be in those groups, so we do some magic: multiply groups assignment by 1 if there is value in first column, and by 0 if not, it makes our empty row group 0, which we at the end named “Remaining”.

#### Validation

```identical(result, test)
# [1] TRUE```

### Puzzle #204

We have table with lists of fruits (I want to think about it as fruit salad bowls :D). And we need to make cross check for them, to tell how they are similar to each other, how many fruits are common for pairs of salads (for example: first salad has 2 fruits common with second, 1 with third and 5 with fourth. Intersection is good concept and tool to use here.

```library(tidyverse)

path = "Power Query/PQ_Challenge_204.xlsx"
input = read_excel(path, range = "A1:D7")
test = read_excel(path, range = "F1:I4")```

#### Transformation

```count_intersections <- function(col_name, df) {
col = df[[col_name]] %>% na.omit()
other_cols = df %>% select(-all_of(col_name)) %>% map(na.omit)

intersection_counts = other_cols %>%
map_int(~ length(intersect(col, .x)))

filtered_counts = intersection_counts[intersection_counts > 0]
filtered_names = names(filtered_counts)

map2_chr(filtered_names, filtered_counts, ~ paste(.x, "-", .y)) %>%
paste(collapse = ", ")
}

result = map_chr(names(input), ~ count_intersections(.x, input))

result1 = tibble(
Column = paste(names(input), "Match"),
Intersections = result
) %>%
separate_rows(Intersections, sep = ", ") %>%
mutate(nr = row_number(), .by = Column) %>%
pivot_wider(names_from = Column, values_from = Intersections) %>%
select(-nr)```

#### Validation

```identical(result1, test)
# [1] TRUE```

### Puzzle #205

We again received data in two separate parts. First table presents number of people with specific answer while second what was the answer. We need to join them and place it in some weird format our boss asked. Let’s do it.

```library(tidyverse)

path = "Power Query/PQ_Challenge_205.xlsx"
input1 = read_excel(path, range = "A2:B13")
input2 = read_excel(path, range = "D2:E13")
test = read_excel(path, range = "H2:L8")```

#### Transformation

```input = left_join(input1, input2, by = "Item")

result = input %>%
arrange(desc(YesNo), Item) %>%
mutate(nr = row_number(), .by = YesNo) %>%
mutate(nr_rem = nr %% 2,
nr_int = ifelse(nr_rem == 1, nr %/% 2 + 1,  nr %/% 2)) %>%
select(-nr) %>%
pivot_wider(names_from = nr_rem, values_from = c(Item, Value),
values_fill = list(Value = 0)) %>%
mutate(Sum = Value_0 + Value_1) %>%
select(YesNo, Item1 = Item_1, Item2 = Item_0, Sum) %>%
mutate(`%age` = Sum/sum(Sum), .by = YesNo) ```

#### Validation

```identical(result, test)
# [1] TRUE```

### Puzzle #206

And here we are in world of fairytales, because I don’t know how to explain sense of this transformation. It looks like Big Bad Wolf comes up and blow away our data along the spreadsheet. And we need to find out how it is even possible. We need to unite, and separate again, pivot longer and back wider so many techniques are used to achieve it.

```library(tidyverse)

path = "Power Query/PQ_Challenge_206.xlsx"
input = read_excel(path, range = "A1:D13")
test  = read_excel(path, range = "F1:K19")```

#### Transformation

```r1 = input %>%
mutate(group = cumsum(is.na(Group1)) + 1) %>%
filter(!is.na(Group1)) %>%
mutate(nr = row_number(), .by = group) %>%
unite("Group", Group1:Group2, sep = "-") %>%
unite("Value", Value1:Value2, sep = "-") %>%
pivot_longer(-c(nr, group), names_to = "Variable", values_to = "Value") %>%
select(-Variable)

rearrange_df <- function(df, part) {
df %>%
filter(group == part) %>%
select(-group) %>%
mutate(col = nr, row = row_number()) %>%
pivot_wider(names_from = col, values_from = Value) %>%
as.data.frame()
}

result = map_df(unique(r1\$group), ~ rearrange_df(r1, .x)) %>%
select(-c(1,2)) %>%
separate_wider_delim(1:ncol(.), delim = "-", names_sep = "-") %>%
mutate(across(everything(), ~ if_else(. == "NA", NA_character_, .)))

names(result) = names(test)```

#### Validation

```all.equal(result, test)
# [1] TRUE```

Remember, always if you have structure to compare which contains NA’s do not identical, but rather all.equals, that can check even NA’s.

Feel free to comment, share and contact me with advices, questions and your ideas how to improve anything. Contact me on Linkedin if you wish as well.

PowerQuery Puzzle solved with R was originally published in Numbers around us on Medium, where people are continuing the conversation by highlighting and responding to this story.