我有一个面板数据，十万家公司，想用xtset 来申明面板数据，但是company name 是字符串
xtset Companyname year
varlist:  Companyname:  string variable not allowed

然后我就encode Companyname， gen(company)  想要把字符串变为数字处理，得到以下结果

encode Companyname, gen(company)
too many values
r(134);
error . . . . . . . . . . . . . . . . . . . . . . . .  Return code 134
        too many values;
        1) You attempted to encode a string variable that takes on
        more than 65,536 unique values.  2) You attempted to tabulate
        a variable or pair of variables that take on too many values.
        If you specified two variables, try interchanging them.
        3) You issued a graph command using the by option.  The
        by-variable takes on too many different values to construct
        a readable chart.
我应该是公司数过多导致的。如何解决？