How to write CSV file data without erasing existing data

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I need to save data in CSV file without it deletes the existing data in the file, just create a new line with the informed data

 material=str(input('Informe o material: '))

 mod_elasticidade=float(input('Informe o modulo de elasticidade do material:'))

 tensao_escoamento=float(input('Informe a tensao de escoamento do material:'))

 historico = open("historico.csv","w")

 linha=str(material)+";"+str(mod_elasticidade)+";"+str(tensao_escoamento)

 historico.write(linha)

 historico.close()
python

1 answer

4

Just change the w for a+, thus:

historico = open("historico.csv", "a+")

linha=str(material)+";"+str(mod_elasticidade)+";"+str(tensao_escoamento)

historico.write(linha)

historico.close()

ps: use the with, so when the block finishes it closes the file alone, so:

material = str(input('Informe o material: '))

mod_elasticidade = float(input('Informe o modulo de elasticidade do material:'))

tensao_escoamento = float(input('Informe a tensao de escoamento do material:'))

linha = str(material)+";"+str(mod_elasticidade)+";"+str(tensao_escoamento)

with open("historico.csv", "a+") as historico:
    historico.write(linha)

  • I swapped "w" for "a+" does not erase the existing data in the file, however it writes the new information in the same line of the existing data, I need to write the data in the next blank line of the file and not in the same line

  • @Fabiodalzotto but it was for the a+ do this, who writes on existing lines is the a without the sign of +, the plus sign moves the pointer to the end, unless it is a BUG, you must have done something else in your script that failed at this, it just wasn’t meant to occur.

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