Question

我想要使用Julia代码num2str中的函数，该函数将在小数点左侧的适当位置添加逗号或指定的定界符，以表示任何有效的Julia编号，包括BigInt和BigFloat。它将返回一个要打印的字符串。

例如：

flt1 = 122234.141567
println("flt1 num2str($flt1) = ", num2str(flt1))
# Expected output is:
flt1 num2str(122234.141567) = 122,234.141567

我想将此功能与print和println内置函数一起使用。

Answer 1

here部分回答了这个问题，即整数。以下函数可以满足浮点数和“大”数字的需求。

"""
 For any valid number, add appropriate delimiters.
 See "Regular Expressions Cookbook," by Goyvaerts and Levithan, O'Reilly, 2nd Ed, 
 p. 402, for Regex that inserts commas into integers returning a string.
"""
function num2str(num::Number; delim=",")
   decimal_point = "."
   str = string(num)
   strs = split(str, decimal_point)
   left_str = strs[1]
   right_str = length(strs) > 1 ? strs[2] : ""
   left_str = replace(left_str, r"(?<=[0-9])(?=(?:[0-9]{3})+(?![0-9]))" => delim)
   decimal_point = occursin(decimal_point, str) ? decimal_point : ""
   return left_str * decimal_point * right_str
end

# Test integers, BigInts, floats, and BigFloats:
int0 = 0
int1 = 123
int2 = 123456789
big1 = big"123"
big2 = big"123456789123456789"
flt1 = 122234.141567
flt2 = 7.12345e9
big3 = big"260123.0"
big4 = big"7.12345e9"

setprecision(20)
println("int0 num2str($int0) \t\t\t\t = ", num2str(int0))
println("int1 num2str($int1) \t\t\t\t = ", num2str(int1))
println("int2 num2str($int2) \t\t\t = ", num2str(int2))
println("big1 num2str($big1) \t\t\t\t = ", num2str(big1))
println("big2 num2str($big2) \t\t = ", num2str(big2))
println("big2 num2str($big2) delim is _ \t = ", num2str(big2, delim="_"))
println("flt1 num2str($flt1) \t\t\t = ", num2str(flt1))
println("flt1 num2str($flt1) delim is _ \t\t = ", num2str(flt1, delim="_"))
println("flt2 num2str($flt2) \t\t\t = ", num2str(flt2))
println("big3 num2str($big3) \t\t\t = ", num2str(big3))
println("big4 num2str($big4) \t\t\t = ", num2str(big4))
println("big4 num2str($big4) delim is _ \t\t = ", num2str(big4, delim="_"))

## ============================== Output ===================================
int0 num2str(0)                                  = 0
int1 num2str(123)                                = 123
int2 num2str(123456789)                          = 123,456,789
big1 num2str(123)                                = 123
big2 num2str(123456789123456789)                 = 123,456,789,123,456,789
big2 num2str(123456789123456789) delim is _      = 123_456_789_123_456_789
flt1 num2str(122234.141567)                      = 122,234.141567
flt1 num2str(122234.141567) delim is _           = 122_234.141567
flt2 num2str(7.12345e9)                          = 7.12345e9
big3 num2str(2.60123e+05)                        = 2.60123e+05
big4 num2str(7.12345e+09)                        = 7.12345e+09
big4 num2str(7.12345e+09) delim is _             = 7.12345e+09

我希望添加逗号分隔符的功能最终将被添加到print/println和/或@printf中。在此之前，这似乎行之有效。

Julia 1.0中的逗号

1 个答案: