shuffleList.groovy

def dash={ symbol , num -> symbol*num}

list= (1..20).toList()
 
5.times { 
    Collections.shuffle(list)  
    println list
}
println  dash('-',35)

(0..<5).each { 
    Collections.shuffle(list)  
    println list
}

println  dash('-',60)
 
for (i in 0..4 )
{
    Collections.shuffle(list)  
    println list
}
println  dash('-',70)

Output :
[1, 7, 19, 6, 16, 5, 3, 11, 20, 2, 18, 10, 13, 8, 9, 17, 12, 14, 15, 4]
[5, 9, 15, 10, 11, 2, 8, 1, 3, 14, 4, 12, 6, 16, 19, 13, 18, 17, 7, 20]
[5, 10, 2, 17, 3, 20, 12, 14, 15, 19, 11, 13, 9, 6, 1, 16, 7, 18, 8, 4]
[18, 15, 6, 12, 20, 1, 5, 9, 10, 4, 2, 11, 16, 8, 7, 14, 17, 13, 19, 3]

[13, 5, 1, 7, 14, 3, 19, 11, 20, 10, 6, 12, 9, 15, 8, 18, 16, 17, 2, 4]

[3, 19, 15, 6, 7, 12, 14, 8, 17, 13, 1, 20, 2, 16, 10, 18, 4, 9, 11, 5]
[6, 13, 5, 7, 3, 8, 18, 12, 10, 19, 17, 1, 14, 4, 11, 15, 20, 9, 16, 2]
[10, 1, 16, 20, 17, 4, 14, 12, 15, 3, 6, 11, 5, 7, 18, 2, 8, 9, 19, 13]
[12, 11, 4, 13, 16, 18, 20, 5, 17, 2, 8, 14, 10, 7, 3, 9, 19, 15, 6, 1]

[6, 20, 18, 1, 19, 12, 17, 2, 7, 13, 14, 16, 8, 3, 10, 15, 9, 5, 4, 11]

[1, 17, 8, 7, 11, 3, 6, 13, 5, 2, 16, 19, 14, 18, 15, 4, 9, 10, 20, 12]
[17, 10, 15, 20, 14, 18, 19, 8, 1, 7, 3, 2, 6, 12, 16, 13, 5, 9, 4, 11]
[14, 10, 12, 13, 20, 18, 7, 4, 5, 3, 19, 9, 15, 6, 2, 11, 1, 17, 8, 16]
[11, 9, 5, 6, 8, 16, 20, 13, 2, 3, 1, 18, 4, 17, 12, 19, 15, 14, 10, 7]

[16, 11, 6, 20, 8, 18, 15, 19, 14, 7, 10, 3, 9, 13, 12, 4, 5, 1, 17, 2]