Consolidate dataframe examples (#18142) #18862
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High-Level OverviewThis PR consolidates all cargo run --example dataframe -- [dataframe|default_column_values|deserialize_to_struct] |
alamb
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alamb
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Thank you @cj-zhukov and @martin-g
I have a suggestion about moving one of these examples to another file -- let me know if it makes sense
| /// | ||
| /// The metadata-based approach provides a flexible way to store default values as strings | ||
| /// and cast them to the appropriate types at query time. | ||
| pub async fn default_column_values() -> Result<()> { |
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I am not quite sure that this is a "dataframe" example -- it does use the DataFrame API but I think it is really illustrating how to provide a custom data source that fills in default column values
I suggest we move it to https://github.com/apache/datafusion/tree/main/datafusion-examples/examples/custom_data_source instead
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Agree with you, let's move the example
| let usage = format!( | ||
| "Usage: cargo run --example {} -- [{}]", | ||
| ExampleKind::EXAMPLE_NAME, | ||
| ExampleKind::variants().join("|") |
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BTW for some reason
cargo run --example dataframedoesn't show me the valid options, it only tells me the argument is missing 🤔
Usage: cargo run --example dataframe -- [dataframe|default_column_values|deserialize_to_struct]
Error: Execution("Missing argument")
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The options are listed here: '-- [dataframe|default_column_values|deserialize_to_struct]'
Maybe another format should be used...
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Thanks! I see what you mean - while the valid options are included in the usage line, they are not very visible, especially since they appear only after the “Missing argument” error.
I agree the formatting could be improved to make the valid options clearer. We could print them separately (as a list) or improve the usage string so it’s easier to read.
I'm happy to adjust the formatting if you have a preferred style, or I can propose one:
Usage:
cargo run --example dataframe <EXAMPLE>
Examples:
dataframe
default_column_values
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I think I just missed the options in my haste. Maybe we can improve the formatting for these errors as some follow on PR
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Which issue does this PR close?
Rationale for this change
This PR is for consolidating all the
dataframeexamples (dataframe, default_column_values, deserialize_to_struct) into a single example binary. We are agreed on the pattern and we can apply it to the remaining examplesWhat changes are included in this PR?
Are these changes tested?
Are there any user-facing changes?