Add ability to get local columns from wrapped functions

[jiffyclub]

The .local_columns attribute on all wrapped tables should now work.
On wrapped functions (both tables and sources), it will evaluate the
function, store frame metadata, and return the frame columns.

For table sources this will also cause the registered table source to be replaced with the data frame, but now the function wrapper object will have working .columns, .local_columns, .index, and len() capabilities.

[jiffyclub]

@fscottfoti You might also find the .convert method on TableSourceWrapper useful. It'll evaluate the source function and return the newly created DataFrameWrapper.

[fscottfoti]

The convert method is handy. Is the right way to use it to call

if isinstance(df, TableSourceWrapper):
    df = df.convert()

I'm curious, why not convert when injected so that no TableSourceWrapper ever gets injected? I mean, once it's injected presumably it will need to be read in so why not convert beforehand?

[jiffyclub]

Yeah that's a good idea.

On Tuesday, July 29, 2014, Fletcher Foti notifications@github.com wrote:

The convert method is handy. Is the right way to use it to call

if isinstance(df, TableSourceWrapper):
df = df.convert()

I'm curious, why not convert when injected so that no TableSourceWrapper
ever gets injected? I mean, once it's injected presumably it will need to
be read in so why not convert beforehand?

—
Reply to this email directly or view it on GitHub
#74 (comment).