Retrieval of data items ของ แม่แบบ:Show data

{{data {{{1}}}|pst2|land area}}, using parameter selection template Template:Pst2, gives the parameter land area, etc.

For retrieval of more data items it is more efficient to prepare a template for that, to be used as follows:

{{data {{{1}}}|template name|..|..|..|..}}

so that this data template needs to be called only once.[2] The default template is Template:Show data, producing this page.

The four parameters are optional, they are passed on to the prepared template as parameters 2-5.

Special templates:

A parameter being undefined or empty typically means the same, see below. {{data ..|pst2|..}} gives the empty string and the text "{{{..}}}", respectively. Therefore an application checking the parameter has to check both. Checking whether a result is equal to e.g. the text "{{{popinc}}}" cannot be done directly with #ifeq in a template which itself has also a parameter with that name, because if that is defined, there would be a comparison with the value instead of the text itself. Instead, it can be checked whether the first character of the result is "{", e.g.: {{#ifeq:{{padleft:|1|{{data {{{continent}}}|pst2|popinc}}}}|{|..|..}}.