The display filter can be customized to your needs. The constructor of the BaseDisplayFilter accepts following
parameters:
| Parameter | Description |
|---|---|
data |
A list of dictionaries to filter on. |
field_names |
A list of field names which are allowed in the display filter. If no field names are given there are no restrictions regarding specifying field names in the display filter query. However, in some cases it may make sense to allow only a set of field names to be queried and disallow others. |
functions |
A dictionary of functions whereby the key specifies the name of the function. If no functions are supplied "len", "lower" and "upper" are used as default ones. If you don't require functions you may provide an empty dictionary. |
slicers |
A list of slicers. If no slicers are supplied the BasicSlicer is used per default. If you require additional slicers you can provide your own list here. |
evaluator |
A evaluator which does the evaluation of the expressions. If no evaluator is defined the DefaultEvaluator is used which supports all kind of types.If you want to down-trim or extend evaluation you can provide a custom evaluator here. |
pydfql defines some custom exceptions which may be thrown during runtime:
| Exception | Description |
|---|---|
ParserError |
This error indicates that there was an error during parsing the display filter which usually happens when the user input (aka the display filter) is not correctly specified. |
EvaluationError |
This error indicates that there was an error during evaluating an expression which usually happens when some illegal operations are performed (e.g. 'lower(int)' -> only works with strings). |
ProgrammingError |
This error indicates an internal error likely due to some programming error. If this error is thrown please open a ticket. |
pydfql defines a set of helpers which may be used in standalone applications:
| Helper Class | Description |
|---|---|
DisplayFilterShell |
A command line loop which allows to filter data on a provided data store. Uses Table to print the result in a pretty table. |
DictDisplayFilterShell |
A command line loop which allows to filter data on a provided data store. Uses DictTable to print the result in a pretty table. |
Table |
Initialized with a data store, provides a filter method, prints results in a pretty table. |
DictTable |
Initialized with a data store, provides a filter method, prints results in a pretty table. |