python read Large integers in excel

Question

I have an excel with following 3 large integers (in fact, they are ids). But in excel it will be stored in scientific mode. And when I use pandas to read the excel, I will lost precision since the integer is too large for int64 to store it.

Example data: (1.xlsx)
76307016609101000000000000000000
86412903902869300000000000000000
35575701294198100000000000000000

A = pd.read_excel("1.xlsx", engine="openpyxl", header=None, dtype=np.float64) 
% no matter what the dtype is the result will be wrong

print(int(A.loc[0])) # 76307016609101001211632066494464 wrong

I don't know whether there's a type of int that's longer than int64 and supported by numpy/pandas. Thank you very much!!

Answer 1

If you can get excel to spit out the raw numbers then you can get around this by reading the numbers as Text

import pandas as pd 
import io

txt='''\
line,Num,text
1,12345678901234435346789012345678901234567890,"large"
2,66464644666669999999999999999999999999999999999999999999999999999999999999991,"larger"
3,1,"unity"
4,-9999999999999999999999999999999999999999,"larger in a different way"
'''

df=pd.read_csv(io.StringIO(txt), converters={'Num':int})

print(df)

results in

   line                                                Num  \
0     1       12345678901234435346789012345678901234567890   
1     2  6646464466666999999999999999999999999999999999...   
2     3                                                  1   
3     4          -9999999999999999999999999999999999999999   

                        text  
0                      large  
1                     larger  
2                      unity  
3  larger in a different way  

and you can still do sums on them

n=df["Num"][1]
print (n,n+1 )

yields

66464644666669999999999999999999999999999999999999999999999999999999999999991 
66464644666669999999999999999999999999999999999999999999999999999999999999992