Excel BI - Excel Challenge 776

excel-challenges

excel-formulas

🔰 Col1 Col2 Answer Expected A H B D C F G

Published

March 24, 2026

Illustration for Excel BI - Excel Challenge 776

Challenge Description

🔰 Col1 Col2 Answer Expected A H B D C F G

Solutions

library(tidyverse)
library(readxl)

path = "Excel/700-799/776/776 Stack.xlsx"
input = read_excel(path, range = "A1:B16")
test  = read_excel(path, range = "D1:D27") %>% pull() %>% str_c(collapse = "")

collapse_column = function(x) {
  str_extract_all(str_c(na.omit(x), collapse = ""), "(.)\\1*")[[1]]
}

result = map2_chr(
  collapse_column(input$Col1),
  collapse_column(input$Col2),
  ~ str_c(.x, .y)
) %>% str_c(collapse = "")

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

Logic: Read the workbook ranges needed for the challenge; Parse the packed text or string structure.
Strengths: The solution stays close to the text pattern itself, which makes the extraction logic easy to audit.
Areas for Improvement: The solution assumes the workbook layout and selected ranges remain stable, so any structural change in the sheet would require small adjustments.
Gem: A small number of well-targeted text patterns does most of the heavy lifting.

import pandas as pd
import re

path = "700-799/776/776 Stack.xlsx"

input = pd.read_excel(path, usecols="A:B", nrows=16)
test = "".join(pd.read_excel(path, usecols="D", nrows=27).iloc[:, 0].astype(str))

def extract_groups(series):
    return [m[0] for m in re.findall(r'((.)\2+|.)', "".join(series.dropna().astype(str)))]

result = "".join(a + b for a, b in zip(*(extract_groups(input.iloc[:, i]) for i in range(2))))

print(result == test) # True

The Python version expresses the core extraction rule directly and keeps the pattern matching easy to review.

Difficulty Level

Medium

The individual steps are manageable, but the correct transformation pattern is not obvious from the raw data.