Forward / Backward Fill
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What is Forward / Backward Fill?
Forward fill (ffill) propagates the last valid value forward to fill subsequent missing entries. Backward fill (bfill) does the reverse, filling from the next valid value. Both are commonly used for time series data where missing values represent periods where the previous or next observation is the best estimate.
Free resources to learn Forward / Backward Fill
- Official docspandas.DataFrame.ffill
- Official docspandas.DataFrame.bfill
- ArticleHow to Fill Missing Data with Pandas
More in stage 9: Data Cleaning
Forward / Backward Fill: common questions
Can I learn Forward / Backward Fill in Hindi?
This lesson is written in English. Once you sign in, open it in the interactive course and ask the AI tutor to explain Forward / Backward Fill in Hindi or Hinglish. The tutor answers from this lesson’s own text, so it stays on the syllabus, and it runs on your own Google, OpenAI or Anthropic key.
Is this Forward / Backward Fill tutorial for beginners?
It is lesson 66 of 112 in the free Python for Data Analysis roadmap, in stage 9, Data Cleaning. If you are new to Python for Data Analysis, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.