Yes, it is possible to create and use hash tables in Excel. One way to do this is by using the
VLOOKUP function in combination with a helper column.
Here are the steps to create a hash table in Excel:
- Create a new column next to your data table. This will be your helper column.
- In the first cell of the helper column, enter the formula =HASHCELL(A2), where A2 is the cell containing the first value in your data table.
- Press Enter to apply the formula to the first cell of the helper column.
- Double-click the fill handle (the small square in the bottom right corner of the cell) to apply the formula to the rest of the cells in the helper column.
- In a new cell, enter the formula =VLOOKUP("value_n",B:C,2,FALSE), where "value_n" is the value you want to look up, and B:C are the columns containing your helper column and the corresponding values.
- Press Enter to apply the formula and get the corresponding value for "value_n".
Here's how the formula in step 2 works:
=HASHCELL(A2)
This formula uses the built-in Excel function
HASHCELL to generate a unique hash value for the value in cell A2. The hash value is a numeric representation of the value that can be used as a lookup key.
You can create a custom function in VBA to use the
HASHCELL function. Here's an example of what the VBA code might look like:
Formula:
Function HASHCELL(value As Variant) As Long
Dim hash As Long
hash = 0
For i = 1 To Len(value)
hash = hash + Asc(Mid(value, i, 1))
Next i
HASHCELL = hash
End Function
This function takes a value as input and returns a hash value as output. The hash value is calculated by adding up the ASCII codes of each character in the value.
Once you have the hash table set up, you can use the
VLOOKUP function to look up values based on their hash values. This can be much faster than using the
FIND function or other methods to search for values in a large data set.
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