Given: L1 = {{x1,y1},{x2,y2},{x3,y3},{x4,y4},...........{xn,yn}}: how is L2 below, obtain:
L2 = {{ax1,y1},{ax2,y2},{ax3,y3},{ax4,y4}.....{axn,yn}}
Or
In[1]:= {a, 1} # & /@ {{x1, y1}, {x2, y2}, {x3, y3}, {x4, y4}} Out[1]= {{a x1, y1}, {a x2, y2}, {a x3, y3}, {a x4, y4}}
(Short notation for In6 in Bill Simpson's list.)
Another solution which makes use of a delayed rule:
In[1]:= L1 = {{x1, y1}, {x2, y2}, {x3, y3}, {x4, y4}, {xn, yn}}; L2 = L1 /. {x_, y_} :> {a x, y} Out[2]= {{a x1, y1}, {a x2, y2}, {a x3, y3}, {a x4, y4}, {a xn, yn}}
In[1]:= Transpose[{a, 1} Transpose[{{x1, y1}, {x2, y2}, {x3, y3}, {x4, y4}, {x5, y5}, {xn, yn}}]] Out[1]= {{a x1, y1}, {a x2, y2}, {a x3, y3}, {a x4, y4}, {a x5, y5}, {a xn, yn}}
