How do I write to the middle of a text file while reading its contents?

Question

First of all thanks for helping me out with moving files and for helping me in with tcl script.

Small doubt i had with python code.. as below..

impor         


        

Answer 1

Actually your method works but your fout is open in append mode. So this is why you can only write at the end. Here is an working example.

# creating a file for reference
ff = open("infiletest","w")
pos_file = {}
for i in range(3):
    pos_file[i] = ff.tell()
    ff.write("%s   21/1/1983\n" % i)
ff.close()

# modify the second line
ff = open("infiletest","r+")
ff.seek(pos_file[2])
ff.write("%s   00/0/0000\n" % 2)
ff.close()

Note that that you overwritte the content of the file.