From Test-Scratch-Wiki

"Random" redirects here. For random page on the wiki, see Special:Random.
隨機取數 () 到 ()
隨機取數 (1) 到 (10)
類別 運算類積木
形狀 橢圓形積木

The Pick Random () to () 積木 is an 運算類積木 and a 橢圓形積木. The block picks a pseudorandom number ranging from the first given number to the second, including both endpoints. If both numbers have no decimals, it will report a whole number. For example, if a 1 and a 3 were inputed, the block could return a 1, 2 or 3. If one of the numbers has a decimal point, even .0, it reports a number with a decimal. For example, if 0.1 and 0.14 were given, the output will be 0.1, 0.11, 0.12, 0.13, or 0.14.

The numbers given with this block are not truly random — they are merely unpredictable. It is nearly impossible to generate truly random numbers using a computer.


Pick Random () to () in Experimental Viewer.png

In the 實驗查看器, the block had a picture of a die on it.


In many types of 專案, random numbers must be picked — this block will easily do the job, without any complicated scripts.

Some common uses for the Pick Random () to () block:

  • Creating randomized levels
當收到訊息 [generate v]
定位到 x: (-50) y: (50)
變數 [square v] 設為 [1]
重複 (121) 次 
  替換第 (square) 項於 [level v] 成 (隨機取數 (1) 到 (10))
  變數 [square v] 改變 (1)
變數 [square v] 設為 [1]
重複 (11) 次 
  重複 (11) 次 
    造型換成 (清單第 (square) 項項目\( [level v] \) :: list)
    x 改變 (10)
    變數 [square v] 改變 (1)
  定位到 x: (-50) y: ((y 座標) - (10))
重複直到 <<(清單第 (start) 項項目\( [level v] \) :: list) = [10]> 不成立> 
  變數 [start v] 設為 (隨機取數 (1) 到 (121))
造型換成 [player v]
變數 [square v] 設為 [1]
定位到 x: (-50) y: (50)
重複直到 <(square) = (start)> 
  如果 <(x座標) = [50]> 那麼 
    定位到 x: (-50) y: ((y 座標) - (10))
    x 改變 (10)
  變數 [square v] 改變 (1)
廣播訊息 [play v]
  • Setting random stats
變數 [hp v] 設為 (隨機取數 (25) 到 (100))
  • Choosing random objects
變數 [purchase v] 設為 (清單第 (隨機取數 (1) 到 (9)) 項項目\( [grocery list v] \) :: list)
造型換成 (隨機取數 (1) 到 (7))


Main article: List of Block Workarounds

To work around this block, the Scratcher must program a 程式 that will give unpredictable numbers.

A simple workaround is to fill a 清單 with the possible numbers, and then use the 清單第 () 項項目 block with the first input set to any. The Item (any) of () block chooses an unpredictable item — so if the chosen list has all the wanted numbers, the Item () of () block is an effective workaround:

當 @greenflag 被點擊
變數 [random number v] 設為 (清單第 (年 v) 項項目\( [list v] \) :: list)

There are scripts that can pick unpredictable numbers without using any blocks that give random values. To make these scripts, a value must be used that is unpredictable — the 計時器 is a very good choice. Other choices are:

  • Continuously moving a hidden sprite around the screen and using its location
  • Continuously changing a 變量 and using its current value
  • Continuously changing the pen color, shade or size and using its value

Then a script can be created with the value — an example with a continuously moving sprite:

變數 [random number v] 設為 (x 座標)

This, however, is rather simple. More complicated scripts can be made:

變數 [random number v] 設為 ((x座標) + (y 座標))
變數 [random number v] 設為 (四捨五入數值 (((y 座標) + ((方向) * (2))) / (3)))
Note Note: The random numbers generated from these alternatives may not be as accurate as the Pick Random () to () block.
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