OpenRefine (ex-Google Refine) is a powerful tool for working with messy data, cleaning it, transforming it from one format into another, extending it with web services, and linking it to databases like Freebase.
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Open Refine / Google Refine
Open Refine is a desktop application that can be used to analyze, transform, annotate and explore tabular data. It proves to be very useful for improving data quality (also known as data cleaning).