package for Mathematica-1

To use a Package, we should load it either Get(<<) or Needs

• Get["package`"] or <<package`: Read the package file and evaluate each expression
   and definition. If a package filename is Filename.m and located in a path Filepath,

       <<Filepath`Filename`

• 
  Needs["package`"] : Read the file only if it has not been read already.

To list the functions defined in the package, we can use Names or ?

• Names["package`*"]: list the the names of the functions.
• ?package`*: list the hyperlinks of the functions

To get the message of a function, use

   ?function

To avoid the collision of a function definitions, use 

   Remove[function]

   to remove the function in Global` context. Note that Clear[exp] is not enough.

To be convenience to load the packages often used, use

   DeclarePackage["newpackage`",{"package1`","package2`",...}],

  and save as mypackages.m. Then load the file as

• <<mypackages.m as your first input when you start a new session.
• put mypackage.m in one of the init.m files and Mathematica will automatically load it whenever you start a session.