p1=[1,2]
p2=[3,4]
xielv=abs((p1[1]-p2[1])/( p1[0]-p2[0]+1e-5))
if xielv>0.25 and xielv<2:
print(xielv)
p1=[1,2]
p2=[3,4]
xielv=abs((p1[1]-p2[1])/( p1[0]-p2[0]+1e-5))
if xielv>0.25 and xielv<2:
print(xielv)