title: findall() or filter() functions with multiple conditions in julia 1.0.3
body: <p>I am trying to convert following python codes to julia 1.0.3</p>
  
  <pre><code>    from numpy import *
      xl,xr,yl,yr = 0,1,0,1
      xs,ys = linspace(xl,xr,N),linspace(yl,yr,N)
  
      x,y = np.meshgrid(xs,ys)
      data=column_stack((ravel(x),ravel(y)))     
      idx1 = where((data[:,0]==xl) | (data[:,0]==xr) | (data[:,1]==yl) | (data[:,1]==yr))
  </code></pre>
  
  <p>I could not convert last  row of the above codes. I came across <code>findall()</code> and <code>filter()</code> functions but could not use them properly in my case</p>