How to review a CSV file before analyzing it
A CSV can be opened in a spreadsheet and still contain errors affecting analysis: incorrect delimiters, empty columns, repeated headers, or mixed data. An initial review helps detect problems before transforming it.
What to review in the structure
Check the number of columns, the name of the headers, and if each row maintains the same structure. Observe if there are commas within text fields or line breaks that should be quoted.
Do not confuse an empty row with a missing value. Decide if the data is absent, if the field does not apply, or if it is an error in capture.
What to review in values
Look for dates with different formats, numbers stored as text, extra spaces, and values that should have leading zeros.
Descriptive statistics help recognize patterns, but do not explain the meaning of the data by themselves. Contrast the results with the origin of the file.
Common questions
Can I detect duplicates with a CSV review?
The review helps inspect the structure, but you must choose a key and a duplication rule suitable for your dataset.
Should I modify the original file?
It is safer to work on a copy and keep an unchanged version for comparison.