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For the efficient retrieval of multiple GRIB keys from a fieldset. A single call to grib_get can replace multiple calls to the other grib_get_* functions and is hence more efficient. The keys are provided as a list for the second argument; by default they will be retrieved as strings, but their type can be specified by adding a modifier to their names, following the convention used by grib_ls where the key name is followed by a colon and then one or two characters which specify the type (:
- s=string
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- l=long
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- d=double
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- la=long array
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- da=double array
- n=native type New in Metview version 5.14.0
). For example, the key 'centre' can be retrieved as a string with 'centre' or 'centre:s', or as a number with 'centre:l'. Each GRIB key has a ‘native type’, e.g. long or string. If the type is specified as “n” then the type that is returned. The native type for the key ‘centre’ is str, so ‘centre:n’ will return a str.
The result is always a list of lists; by default, or if the optional third argument is 'field', the result will be grouped by field, containing one list per field, each of these lists containing one element per key; if the optional third parameter is 'key', the result will be grouped by key, containing one list per key, each of these lists containing one element per field. Example - the following lines of Macro code on a particular 6-field fieldset:
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