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Groovy Series: Numbers

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  1. //the two most common number classes
  2. def intObj = 5
  3. assert intObj.class.name == 'java.lang.Integer'
  4.  
  5. def bigDecimalObj = 5.12345
  6. assert bigDecimalObj.class.name == 'java.math.BigDecimal'
  7.  
  8. //you can explicitly create Long, Float and Double with L / F / D
  9. def longObj = 20L
  10. assert longObj.class.name == 'java.lang.Long'
  11. def floatObj = 40.45F
  12. assert floatObj.class.name == 'java.lang.Float'
  13. def doubleObj = 34.45D
  14. assert doubleObj.class.name == 'java.lang.Double'
  15.  
  16. //if G is used, it checks if the number has a decimal point, then creates a BigInteger or BigDecimal
  17. def bigIntegerObj = 50G
  18. assert bigIntegerObj.class.name == 'java.math.BigInteger'
  19.  
  20. //some coercion stuff
  21. //multiplication, addition and substraction between two floats results in a double
  22. def z = 2F * 2F
  23. assert z.class.name == 'java.lang.Double'
  24.  
  25. //multiplication, addition and substraction with BigInteger or BigDecimal results in BigInteger or BigDecimal
  26. def product = 1.1G * 2 //BigDecimal and Integer
  27. assert product.class.name == 'java.math.BigDecimal'
  28.  
  29. (3G*4).class.name == 'java.math.BigInteger' //BigInteger and Integer
  30.  
  31. //multiplication of two integers
  32. assert (5*4).class.name == 'java.lang.Integer'
  33.  
  34. //multiplication with Long
  35. assert (1L*4).class.name == 'java.lang.Long'
  36.  
  37. //dividing some numbers
  38. (5/5).class.name == 'java.math.BigDecimal'
  39. //if you want an integer, use the intdiv() method
  40. (5.intdiv(5)).class.name == 'java.lang.Integer'
  41. (1.intdiv(5)).class.name == 'java.lang.Integer' //result is 0
  42. assert 1/2 == 0.5
  43.  
  44.  
  45. //some GDK methods for numbers
  46. //think about a java for loop... you don't need it!
  47. def numbers = []
  48. 10.times { numbers << it } //it will contain values from 0 to 9
  49. assert numbers.join(",") == '0,1,2,3,4,5,6,7,8,9'
  50. 10.upto(12) { numbers << it}
  51. assert numbers.join(",") == '0,1,2,3,4,5,6,7,8,9,10,11,12'
  52. 11.downto(10) { numbers << it}
  53. assert numbers.join(",") == '0,1,2,3,4,5,6,7,8,9,10,11,12,11,10'
  54.  
  55. numbers = []
  56. 1.step(2, 0.1) { numbers << it; assert it.class.name == 'java.math.BigDecimal' }
  57. assert numbers.join(",") == '1,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9' //notice 2 is not included
  58.  
  59. numbers = []
  60. 1.0.step(2, 0.1) { numbers << it; assert it.class.name == 'java.math.BigDecimal' }
  61. assert numbers.join(",") == '1.0,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9' //notice how the first value changed to 1.0

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