Argthtjtr

I am trying to draw a simple probability tree, where the probabilites could sometimes be fraction or decimals., this means, I will have to adjust the spacing. So I tried the below code. This produces tree but label gone, and error thrown.

documentclass{article}

usepackage[utf8]{inputenc}



usepackage[linguistics]{forest}

usepackage{philex}





forestset{

  my edge label/.style 3 args={

    edge label={node[midway, font=sffamilyscriptsize, #1,xshift=#2]{#3}},

  },

}



title{Problem customizing forest tree}

author{parthi292929 }

date{November 2018}







begin{document}



maketitle



section{Introduction}



    scalebox{1.2}{

        begin{forest}

        for tree={grow'=east}

          [0

            [Diseased, my edge label={above}{xshift=-2mm}{0.002}

             [Positive

             ]

             [Negative(FN)

             ]

            ]

            [No Disease

             [Positive

             ]

             [Negative

             ]        

            ]

            ]

          ]

        end{forest}

    }





end{document}

Output:

Error:

There are actually 2 issues.

1. 
   style 3 args does not exist, use style n args={3}{... instead.


2. You define for the 2nd argument xshift=#2 but add one more xshift when you are saying my edge label={above}{xshift=-2mm}{0.002}.

Working code:

documentclass{article}

usepackage[utf8]{inputenc}



usepackage[linguistics]{forest}

usepackage{philex}





forestset{

  my edge label/.style n args={3}{

    edge label={node[midway, font=sffamilyscriptsize, #1,xshift=#2]{#3}},

  },

}



title{Problem customizing forest tree}

author{parthi292929 }

date{November 2018}







begin{document}



maketitle



section{Introduction}



    scalebox{1.2}{

        begin{forest}

        for tree={grow'=east}

          [0

            [Diseased,my edge label={above}{-2mm}{0.002}

             [Positive

             ]

             [Negative(FN)

             ]

            ]

            [No Disease

             [Positive

             ]

             [Negative

             ]        

            ]

            ]

          ]

        end{forest}

    }





end{document}

Simpler code: pgfkeys already accept comma-separated arguments, which is illustrated in my edge label={above,xshift=-3mm}{0.002}. And instead the xshift you my just use above left or below left etc., as in my edge label={below left}{0.998}.

documentclass{article}

usepackage[utf8]{inputenc}



usepackage[linguistics]{forest}

usepackage{philex}





forestset{

  my edge label/.style n args={2}{

    edge label={node[midway, font=sffamilyscriptsize,#1]{#2}},

  },

}



title{Problem customizing forest tree}

author{parthi292929 }

date{November 2018}







begin{document}



maketitle



section{Introduction}



    scalebox{1.2}{

        begin{forest}

        for tree={grow'=east}

          [0

            [Diseased,my edge label={above,xshift=-3mm}{0.002}

             [Positive

             ]

             [Negative(FN)

             ]

            ]

            [No Disease,my edge label={below left}{0.998}

             [Positive

             ]

             [Negative

             ]        

            ]

            ]

          ]

        end{forest}

    }





end{document}