Find element in a list matching a pattern (using wildcards)

Question

Somehow, I did not manage to find anything related to that. Suppose, in my Global list of variables, I would like to make a search such that I obtain all the elements in the list which start with func. Trying the naive choice of

Cases[Names["Global`*"], func_]

does not work, however I cannot see how to make this work?

Answer 1

You can use PatternTest (?) with StringMatchQ

Cases[Names["Global`*"], _?(StringMatchQ["func*"])]

or with StringStartsQ

Cases[Names["Global`*"], _?(StringStartsQ["func"]) ]

Note the redundant-looking (..) after ?.

Alternatively, you can use Condition (/;)

Cases[Names["Global`*"], x_ /; StringMatchQ[ x, "func*"] ]
Cases[Names["Global`*"], x_/;StringStartsQ[ x, "func"] ]

Answer 2

Or, if you are not wedded to Cases and patterns, you could use Select and a predicate, something like

Select[Names["Global`*"], StringStartsQ["func"]]

Answer 3

Why not simply include the pattern in Names?

In[1]:= Names["System`Plot*"]

Out[1]= {"Plot", "Plot3D", "Plot3Matrix", "PlotDivision", \
"PlotJoined", "PlotLabel", "PlotLabels", "PlotLayout", "PlotLegends", \
"PlotMarkers", "PlotPoints", "PlotRange", "PlotRangeClipping", \
"PlotRangeClipPlanesStyle", "PlotRangePadding", "PlotRegion", \
"PlotStyle", "PlotTheme"}