How to write a UTF-8 file?

Question

s = OpenWrite[ofile, CharacterEncoding -> "UTF8"]
Export[s, "∂f/∂t"]
Close[s]

did not successfully write ∂ into the file. Instead, it writes the InputForm. How to let it write ∂?

Answer 1

F'x is correct. Using WriteString is the method to use. If you want to write a "big expression", try the following.

Let's assume a large matrix with dimensions of 100 by 5;

a = RandomReal[{1,10},{100,5}]

We can easily write this using the WriteString method.

s = OpenWrite["~/Desktop/toto.txt", CharacterEncoding -> "UTF8"]
WriteString[s, a]
Close[s]

This will write to the text file exactly as you see it printed in the notebook interface.

You can also print in Grid or TableForm

a = RandomReal[{1,10},{100,5}]//TableForm

You can also get a little crazy and riffle in delimiters...

a = "a =   "<> StringJoin[Riffle[ToString[#^2] & /@ Range[10], "\t"]]

Also, don't forget the OpenAppend function to write data at the end of a file without overwriting existing info.

b = "b =   " <> StringJoin[Riffle[ToString[#^3] & /@ Range[10], "\t"]]
s = OpenAppend["~/Desktop/toto.txt", CharacterEncoding -> "UTF8"]
WriteString[s, "\n"]
WriteString[s, b]
Close[s]

Answer 2

WriteString:

s = OpenWrite["~/Desktop/toto.txt", CharacterEncoding -> "UTF8"]
WriteString[s, "\[PartialD]f/\[PartialD]t"]
Close[s]