Replace values in Power BI - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ dax_lod_result

intermediate

Replace values in a column using DAX

You have a column 'Status' with values 'Pending', 'In Progress', and 'Completed'. You want to create a new calculated column that replaces 'Pending' with 'Not Started' and keeps other values unchanged. Which DAX expression produces the correct result?

A NewStatus = SUBSTITUTE(Table[Status], "Pending", "Not Started")

B NewStatus = SWITCH(Table[Status], "Pending", "Not Started", Table[Status])

C NewStatus = REPLACE(Table[Status], 1, 7, "Not Started")

D NewStatus = IF(Table[Status] = "Pending", "Not Started", Table[Status])

💡 Hint

Use a conditional function that checks the value and replaces only when it matches.

Option D uses IF to check if the value is 'Pending' and replaces it with 'Not Started'. Other values remain unchanged.

Option D also works because the last argument in SWITCH acts as the default for unmatched cases, but IF is more straightforward for a single replacement.

Option D tries to replace characters by position, which is not suitable here.

Option D replaces substring occurrences, which could cause unintended replacements if 'Pending' appears inside other words.

❓ visualization

intermediate

Visualizing replaced values in a report

You replaced 'Pending' with 'Not Started' in your data model. You want to create a bar chart showing counts of each status including the replaced value. Which visualization setup is best practice?

A Use a slicer to filter only 'Pending' values and show counts.

B Use the original 'Status' column on the axis and count of rows as values.

C Use the new calculated column 'NewStatus' on the axis and count of rows as values.

D Use a pie chart with original 'Status' column and replace labels manually.

💡 Hint

Use the column that contains the replaced values for accurate visualization.

Option C is correct because it uses the new column with replaced values, so the chart reflects the updated categories.

Option C shows original values, so 'Pending' will appear instead of 'Not Started'.

Option C filters only 'Pending', ignoring other statuses.

Option C requires manual label changes, which is error-prone and not dynamic.

❓ data_modeling

advanced

Replacing multiple values in a column efficiently

You want to replace multiple values in a 'Category' column: 'A' → 'Alpha', 'B' → 'Beta', 'C' → 'Gamma'. Which DAX expression correctly creates a new column with these replacements and keeps other values unchanged?

A NewCategory = SWITCH(Table[Category], "A", "Alpha", "B", "Beta", "C", "Gamma", Table[Category])

B NewCategory = REPLACE(Table[Category], 1, 1, "Alpha")

C NewCategory = IF(Table[Category] = "A", "Alpha", IF(Table[Category] = "B", "Beta", IF(Table[Category] = "C", "Gamma", Table[Category])))

D NewCategory = SUBSTITUTE(Table[Category], "A", "Alpha")

💡 Hint

Use a function that handles multiple conditions with a default fallback.

Option A uses SWITCH with multiple replacements and a default fallback to original value, which is efficient and clear.

Option A is correct logically but more complex and nested; however, it also works but is less efficient.

Option A replaces characters by position, which is incorrect for categorical replacements.

Option A replaces substring 'A' everywhere, which can cause wrong replacements.

🔧 Formula Fix

advanced

Identify the error in this value replacement DAX

This DAX expression aims to replace 'Old' with 'New' in 'Status' column but causes an error. What is the error?

Power BI

NewStatus = IF(Table[Status] == "Old", "New", Table[Status])

A Runtime error: Table[Status] column not found.

B SyntaxError: '==' is invalid in DAX; use single '=' for comparison.

C No error; expression works correctly.

D TypeError: Cannot compare text with '==' operator.

💡 Hint

Check the operator used for comparison in DAX.

DAX uses a single '=' for equality comparison, not '=='. Using '==' causes a syntax error.

Option B is incorrect because '==' is a syntax error, not a type error.

Option B is wrong; the expression does not work.

Option B is unrelated to the operator used.

🧠 Conceptual

expert

Best practice for replacing values in large datasets

You have a large dataset with millions of rows. You need to replace several values in a column. Which approach is best for performance and maintainability?

A Create a separate mapping table with old and new values and use a relationship to replace values via LOOKUPVALUE.

B Use nested IF statements in a calculated column to replace values directly.

C Use REPLACE function to substitute values by character position in the column.

D Manually edit the source data file to replace values before loading.

💡 Hint

Consider scalability and ease of updates when choosing replacement methods.

Option A is best because a mapping table allows easy updates and efficient lookups without complex nested logic.

Option A becomes hard to maintain and slow with many replacements.

Option A is not suitable for categorical replacements.

Option A is error-prone and not scalable for ongoing data refreshes.