Save data in. xlsx format with pandas

Question

Good afternoon! I want to save in a file . xlsx the loop number that my code is running, but the way it is, saves only the last loop.

import time
import pandas as pd

loop = 0

print('Loop')

writer = pd.ExcelWriter('/home/pi/Área de Trabalho/saidaCamera3.xlsx')


while True:
        loop = loop + 1

        df = pd.DataFrame({'Loop': [loop]})
        df.to_excel(writer, 'Camera RGB', index=False)
        writer.save()
        if loop>=32:
            break

writer.save()

It seems a bit silly, but then I’ll join with my sensor reading.

Answer 1

The problem is that with every passage in the loop, you are creating a DataFrame new. Change your code to the following:

import time
import pandas as pd

loop = 0

df = pd.DataFrame()

while True:
    loop = loop + 1
    print('Loop: ', loop)
    df = df.append({'Loop': [loop]}, ignore_index=True)

    if loop >= 32:
        break

print(df.shape)

df.to_excel('/home/pi/Área de Trabalho/saidaCamera3.xlsx', index = False)

Note that the initialization of DataFrame is out of the loop, and that with each passage through this, a new line is added. At the end of the loop, DataFrame is persisted in Excel file.