Python pandas – Does read_csv keep file open?

If you pass it an open file it will keep it open (reading from the current position), if you pass a string then read_csv will open and close the file.

In python if you open a file but forget to close it, python will close it for you at the end of the function block (during garbage collection).

def foo():
    f = open("myfile.csv", "w")
    ...
    f.close()  # isn't actually needed

i.e. if you call a python function which opens a file, unless the file object is returned, the file is automagicallymatically closed.

Note: The preferred syntax is the with block (which, as well as closing f at the end of the with block, defines the f variable only inside the with block):

def foo():
    with open("myfile.csv", "w") as f:
        ...