how to get cell with column or row header text?

[NaughtDZ]

for example(I use vb.net):

'I change column "A" header to "numbers"
sheet.ColumnHeaders(0).Text = "numbers"

Dim num1 as Long = sheet("number",0) 'not correct
Dim num1 as Long = sheet("number")(0) 'not correct
Dim num1 as Long = sheet(number0) 'not correct

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So how to get cell with column name.
I need to handle a table with very many columns. If I were to remember each column of items and their location, such as what column A is and what column B is, writing code would drive me crazy.
I really hope that processing in reorrid is as simple as Pandas in Python.
Just like:
for i in df.index:
df.loc[i,'max']= df['usernum'][i]/2
df.loc[i,'KK'] = df['pos'][i]/2