29 — Playlist: shuffling the order once

Shuffle in a music app does not keep picking any song at random — that would play the same song twice in a row. It mixes the order once and then plays through it. One list of songs is all you need.

#Steps

1. Make the list of songs:

   set songs to list of Blue, Green, Red, Gold
   show songs joined by comma
   

   copyrun it →

   They come out in the order you wrote them.

2. shuffle mixes the order. It goes in the same place as sort from guide 52, and it changes the list itself:

   set songs to list of Blue, Green, Red, Gold
   shuffle songs
   show songs joined by comma
   

   copyrun it →

   A different order every run. No song is lost or repeated — it is the same four songs in another order.

3. Play through the shuffled order. with place from guide 21 says which song you are on:

   set songs to list of Blue, Green, Red, Gold
   shuffle songs
   for each song in songs with place
       show place
       show song
   end
   

   copyrun it →

4. Wait while a song plays. A pause stands in for the real playing:

   set songs to list of Blue, Green
   for each song in songs
       show song
       wait 0.5 seconds
   end
   

   copyrun it →

5. The whole thing:

   set songs to list of Blue, Green, Red, Gold
   shuffle songs
   show todays running order
   for each song in songs with place
       clear the screen
       show place
       show song
       wait 0.5 seconds
   end
   show that was all of them
   

   copyrun it →

#Try it yourself

Delete shuffle songs and run it again — the order never changes. Put sort songs there instead and it plays alphabetically. All three are one sentence in the same place.

#What you learned

• shuffle <list> mixes the order at random, losing and repeating nothing.
• Shuffling once and playing through is what an app actually does.
• shuffle, sort and reverse are the same kind of sentence: they change the list itself.
• with place lets you show which song is playing.