CODEWITHSUNDEEP
pythoncsvfwrite
Klausos Klausos
Klausos Klausos

Reputation: 16050

Add new lines to CSV file at each iteration in Python

I have the following code in Python. I need to execute the function dd.save() N times, each time adding some new lines to the file test.csv. My current code just overrides the content of the file N times. How can I fix this issue?

def save(self):  

    f = csv.writer(open("test.csv", "w"))

    with open("test.csv","w") as f:
        f.write("name\n")
        for k, v in tripo.items():
            if v:
                f.write("{}\n".format(k.split(".")[0]))
                f.write("\n".join([s.split(".")[0] for s in v])+"\n")


if __name__ == "__main__":
    path="data/allData"

    entries=os.listdir(path)

    for i in entries:
      dd=check(dataPath=path,entry=i)
      dd.save()
      print(i)

Upvotes: 1

Views: 2182

Answers (1)

Yasel
Yasel

Reputation: 3120

The most commonly-used values of mode are 'r' for reading, 'w' for writing (truncating the file if it already exists), and 'a' for appending (which on some Unix systems means that all writes append to the end of the file regardless of the current seek position).

Open the file in append mode:

with open("test.csv","a") as f:
        f.write("name\n")

Check docs here.

Upvotes: 4

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