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How to update a particular cell value in pandas DataFrame

Retrieving a single cell value or setting up the single cell value of a row in pandas dataFrame is sometime required when you dont want to create a new Dataframe for just updating that single cell value. You can retrieve and updates values from DataFrame using the following methods.

  1. .loc[]
  2. .iloc[]
  3. .at[]
  4. .iat[]

Create a DataFrame with values

Set a particular cell value using DataFrame.loc[]

DataFrame.loc[] - selects subsets of rows and columns by label only.

Above code update third row of 'TotalMarks' column to 111 using DataFrame.loc[] .


Set a particular cell value using DataFrame.loc[]
DataFrame.iloc - selects subsets of rows and columns by integer location only.

Above code update third row of 'TotalMarks' column to 222 using DataFrame.iloc[] .

Set a particular cell value using DataFrame.iloc[]


Set a particular cell value using DataFrame.iloc[]

Also, you can use .at[] or .iat[] for setting a particular cell value. But it is not recommended their usage unless you have a very time-sensitive application.

Set a particular cell value using DataFrame.at[]

DataFrame.at[ ] - selects a single scalar value in the DataFrame by label only.

Above code update third row of 'TotalMarks' column to 333 using DataFrame.at[] .


Set a particular cell value using DataFrame.at[]

Set a particular cell value using DataFrame.iat[]

DataFrame.iat[] - selects a single scalar value in the DataFrame by integer location only.

Above code update third row of 'TotalMarks' column to 444 using DataFrame.iat[] .


Set a particular cell value using DataFrame.iat[]

SettingWithCopy warning

The crucial problem with chained indexing is when you assigning new values to the subset, in which DataFrame will usually alert the SettingWithCopy warning . This warning alert you that your DataFrame operation might not have worked as expected and that you should check the result and to make sure that you haven't made a mistake. May be you are tempting to ignore this warning if your code still works as expected. Actually, this is not a good practice and never be ignored this warning. Take some time to review your code and clarify why you are getting this warning.










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