st: importing txt file changes format of variable

["Ms. Marilyn Ibarra" <ibarra@uga.edu>]

I have the following data in a txt file:

us_id       firm
000007       x
010234       y
321098       z
112411       w

When I import it into stata I get this:

us_id       firm
7            x
10234        y
321098       z
112411       w

Where the us_id changes in the first two observations (it changes for any observations that have a us_id with zeros at the beginning).  I need us_id to be a 6 digit id number for each firm (ncluding any zeros at the beginning).  This needs to be a string variable but is a numeric variable when imported into STATA.  

Have any idea on how to fix this problem?  

Thanks in advance,
Marilyn. 

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