Locate records in big data file

The text file PersonnelInfo.txt is used to store a great deal of employee data. Please find the data of first 50 male employees in the Texas.

Solution:

A B
1 =file("PersonnelInfo.txt")
2 =A1.cursor@t()
3 =A2.select(Gender=="M"&&State=="TX")
4 =A3.fetch(50)
5 >A3.close()

When handling the big data text, the data neither can be all read into the memory, nor partly selected with SQL as we usually do for database. Under this circumstance, the cursor can be of great help.

In A4, retrieve the required data of the first 50 employees. The result is shown below: