does the strings in Zoho Creator starts with "." ?

does the strings in Zoho Creator starts with "." ?

I am trying to get a number from US Format "11.11" to European Format "11,11" using strings and the built in function: "replaceFirst".  However I found an interesting behaviour:

 tmp_string_price_ = "abcde";

 tmp_string_price = tmp_string_price_.replaceFirst("c",",");

returns "ab,de" as it should be

however 

 tmp_string_price_ = "ab.de";

returns

",b.de"

Correspondingly, it seems that an "."  is found at the first position, even if is not what I have stored in that string.

Obviously, with numbers works similar:

 tmp_string_price_ = "12.34";

 tmp_string_price = tmp_string_price_.replaceFirst(".",",");

returns ",2.34" instaed of 12,34

Any idea how to proceed ? Why is the "." found in the first place of a string?

Thanks

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PS: In the meanwhile I have checked that the system detects the "." in the 2 position (indexOf) and calculates also the right prefix (getPrefix)

But despite of the correct index and the correct prefix, the replacement occurs on the wrong place.

workaround: get prefix, get sufix and add prefix +","+sufix, however I think something weird is here