森林：where 语句中的逻辑和条件

Question

&我怎样才能在条件中包含一个逻辑，where以便条件不匹配只有一个孩子的父母 4-8，以便他们正常地南北生长？即将条件更改为类似以下内容：where n children=0 & parent.n children>1

平均能量损失

\documentclass[border=1cm]{standalone}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
for tree={
    draw=black,align=center,parent anchor=south, child anchor=north,
    edge path={
        \noexpand\path[\forestoption{edge}]
        (!u.parent anchor) -- +(0,-0.125in) -|
        (.child anchor)\forestoption{edge label};
    },
    where n children=0{
        child anchor=west,
        for parent={
            parent anchor=south,
            grow'=east,calign=child edge
        }
    }{}
}
[Root
    [Parent 1
        [,phantom]
        [Child 1]
        [Child 2]
        [Child 3]
    ]
    [Parent 2
        [Child 1
            [,phantom]
            [Child 1]
            [Child 2]
        ]
    ]
    [Parent 3
        [,phantom]
        [Child 1]
        [Child 2]
        [Child 3]
    ]
    [Parent 4
        [Only Child 1]
    ]
    [Parent 5
        [Only Child 1]
    ]
    [Parent 6
        [Only Child 1]
    ]
    [Parent 7
        [Only Child 1]
    ]
    [Parent 8
        [Only Child 1]
    ]
]
\end{forest}
\end{document}

Answer 1

我认为这是解决你的问题的方法：

\documentclass[border=1cm]{standalone}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
for tree={
    draw=black,align=center,parent anchor=south, child anchor=north,
    edge path={
        \noexpand\path[\forestoption{edge}]
        (!u.parent anchor) -- +(0,-0.125in) -|
        (.child anchor)\forestoption{edge label};
    },
    if={level>0}{% skip root (reason: root has no parent)
        if={n_children==0 && n_children("!parent")>1}{% changed to if and added additional condition
            child anchor=west,
            for parent={
                parent anchor=south,
                grow'=east,calign=child edge
            }
        }{}
    }{}
}
[Root
    [Parent 1
        [,phantom]
        [Child 1]
        [Child 2]
        [Child 3]
    ]
    [Parent 2
        [Child 1
            [,phantom]
            [Child 1]
            [Child 2]
        ]
    ]
    [Parent 3
        [,phantom]
        [Child 1]
        [Child 2]
        [Child 3]
    ]
    [Parent 4
        [Only Child 1]
    ]
    [Parent 5
        [Only Child 1]
    ]
    [Parent 6
        [Only Child 1]
    ]
    [Parent 7
        [Only Child 1]
    ]
    [Parent 8
        [Only Child 1]
    ]
]
\end{forest}
\end{document}