Merge pull request JuliaLang#14377 from sarvjeetsinghghotra/issue-14291

RFC: Modified writedlm() to write leading zeros when writing floats JuliaLang#14291

base/grisu.jl

@@ -127,7 +127,7 @@ Base.showcompact(io::IO, x::Float16) = _show(io, x, PRECISION, 5, false)
 
 # normal:
 # 0 < pt < len ####.#### len+1
-# pt <= 0 .000########  len-pt+1
+# pt <= 0 0.000######## len-pt+1
 # len <= pt (dot) ########000. pt+1
 # len <= pt (no dot) ########000 pt
 # exponential:
@@ -149,8 +149,8 @@ function _print_shortest(io::IO, x::AbstractFloat, dot::Bool, mode, n::Int)
  write(io, dec(e))
  return
  elseif pt <= 0
- # => .000########
- write(io, '.')
+ # => 0.000########
+ write(io, "0.")
  while pt < 0
  write(io, '0')
  pt += 1

test/datafmt.jl

@@ -93,6 +93,18 @@ let x = [1,2,3], y = [4,5,6], io = IOBuffer()
  @test readcsv(io) == [x y]
 end
 
+let x = [0.1 0.3 0.5], io = IOBuffer()
+ writedlm(io, x, ", ")
+ seek(io, 0)
+ @test readall(io) == "0.1, 0.3, 0.5\n"
+end
+
+let x = [0.1 0.3 0.5], io = IOBuffer()
+ writedlm(io, x, ", ")
+ seek(io, 0)
+ @test readcsv(io) == [0.1 0.3 0.5]
+end
+
 let x = ["abc", "def\"ghi", "jk\nl"], y = [1, ",", "\"quoted\""], io = IOBuffer()
  writedlm(io, zip(x,y), ',')
  seek(io, 0)