OpenRefine

[OpenRefine] is a power tool for working with messy data, cleaning it up, transforming it from one format into another, extending it with web services, and linking it to databases like Freebase.

OpenRefine has features for manipulating large data sets.

• Importing
• Filtering / faceting
• Editing:
  • Editing cells, editing cells by Clustering
  • Editing columns, creating columns by Extending data
  • Editing rows
  • Understanding expressions
  • Understanding regular expressions
• Exporting
• History (undo/redo)