Question

有一种方法可以访问x（）范围内的阴影变量a的值

function x () { 
  a = 1;  

  function foo() { 
    a = 2;              
    console.log(a);
  }
                  
  foo();
};  

x();
console.log(window.a);

Answer 1

阅读You Don't Know JS的“范围和闭包”部分，其解释清楚

尝试一下：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-113-b763d83160d2> in <module>
     32                        ),
     33                     row = rownum,
---> 34                     col = colnum,
     35 #                     marker_size = 5)
     36                   )

~\Anaconda3\lib\site-packages\plotly\basedatatypes.py in add_trace(self, trace, row, col, secondary_y)
   1648             rows=[row] if row is not None else None,
   1649             cols=[col] if col is not None else None,
-> 1650             secondary_ys=[secondary_y] if secondary_y is not None else None,
   1651         )
   1652 

~\Anaconda3\lib\site-packages\plotly\basedatatypes.py in add_traces(self, data, rows, cols, secondary_ys)
   1719         # Validate rows / cols
   1720         n = len(data)
-> 1721         BaseFigure._validate_rows_cols("rows", n, rows)
   1722         BaseFigure._validate_rows_cols("cols", n, cols)
   1723 

~\Anaconda3\lib\site-packages\plotly\basedatatypes.py in _validate_rows_cols(name, n, vals)
   1562 
   1563             if [r for r in vals if not isinstance(r, int)]:
-> 1564                 BaseFigure._raise_invalid_rows_cols(name=name, n=n, invalid=vals)
   1565         else:
   1566             BaseFigure._raise_invalid_rows_cols(name=name, n=n, invalid=vals)

~\Anaconda3\lib\site-packages\plotly\basedatatypes.py in _raise_invalid_rows_cols(name, n, invalid)
   1551         )
   1552 
-> 1553         raise ValueError(rows_err_msg)
   1554 
   1555     @staticmethod

ValueError: 
        If specified, the rows parameter must be a list or tuple of integers
        of length 1 (The number of traces being added)

        Received: [2]

有没有办法访问阴影变量？

1 个答案: