ΔE 15.4, loose: different enough that you should pick on purpose. Purple Shadow is noticeably lighter, more muted, warmer than Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Purple Shadow is noticeably lighter, more muted, warmer than Purple.
The same difference applies the other way round: Purple is noticeably darker, more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Purple on the colour wheel See Purple Shadow on the colour wheel
All matches: Purple equivalents · Purple Shadow equivalents