CSV and text file import in Power BI - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding CSV import delimiters

You import a CSV file into Power BI. The file uses semicolons (;) to separate values instead of commas (,). What must you do to correctly import the data?

A Rename the file extension from .csv to .txt before importing.

B Change the delimiter setting in the import options to semicolon.

C Open the file in Excel first and save it as a comma-separated CSV.

D No action needed; Power BI automatically detects semicolons.

💡 Hint

Think about how Power BI knows where one value ends and another begins.

Power BI needs to know the delimiter used in the file. If the file uses semicolons, you must specify this in the import settings to parse the data correctly.

❓ dax_lod_result

intermediate

Result of importing CSV with missing headers

You import a CSV file without headers into Power BI and choose the option 'Use first row as headers'. What will happen to the first row of data?

A The first row will be used as column headers and will not appear as data.

B The first row will be imported as data and also as headers, causing duplication.

C Power BI will generate default column names and keep the first row as data.

D The import will fail with an error about missing headers.

💡 Hint

Consider what the 'Use first row as headers' option does.

This option tells Power BI to treat the first row as column names, so it will not be included as data.

🔧 Formula Fix

advanced

Fixing import errors with text qualifiers

You import a CSV file where some fields contain commas inside quotes, like "New York, NY". After import, these fields are split incorrectly. Which option fixes this issue?

A Remove all commas from the CSV file before importing.

B Change the delimiter to a tab character.

C Set the text qualifier to double quotes (") in the import settings.

D Import the file as Excel instead of CSV.

💡 Hint

Think about how Power BI knows to treat commas inside quotes as part of the same field.

Text qualifiers tell Power BI to treat text inside quotes as a single field, even if it contains commas.

❓ visualization

advanced

Visualizing data quality after CSV import

You imported a CSV file with sales data. Some rows have missing values in the 'Sales Amount' column. Which visualization best helps identify how many rows have missing sales amounts?

A A pie chart showing total sales amount by product category.

B A scatter plot of sales amount versus quantity sold.

C A line chart showing sales amount over time.

D A bar chart showing count of rows grouped by whether 'Sales Amount' is blank or not.

💡 Hint

Focus on counting missing versus present values.

A bar chart grouped by blank or not blank values clearly shows how many rows have missing sales amounts.

🎯 Scenario

expert

Handling large CSV files with incremental refresh

Your company receives daily CSV files with millions of rows. You want to import these files into Power BI efficiently and update the data daily without reloading all historical data. What is the best approach?

A Use Power BI incremental refresh with a date column to load only new data each day.

B Manually append each daily CSV file to the existing dataset in Power BI Desktop.

C Import all CSV files into one large table every day, replacing the old data.

D Split the CSV files into smaller chunks and import each separately without refresh.

💡 Hint

Think about how to avoid reloading all data every day.

Incremental refresh allows Power BI to load only new or changed data based on a date column, improving performance with large datasets.