[Tutor] help on string replacement in a file

[klappnase]

On Wed, 06 Aug 2003 12:22:34 +0800
"kamariah lamim" <klhjhm@hotmail.com> wrote:

> Hi.
>    I wrote a function to replace a string in a file.I used built-in replace( 
> ) to do that . However it failed to overwrite the old content of file with 
> the new one. . Could someone trace this problem.the function is something 
> like this:
> 
> lineseen=0
> drot='0.678'
> batchNo=1
> 
> def modify5File(drot,batchNo):
> 	global lineSeen
> 	updateFile=open('disper.501','rw')
> 	x=updateFile.readlines()
> 	for everyLine in x:
> 		lineSeen += 1
> 		if lineSeen == 10:
> 			string.replace(everyLine,'+0.2000000000d+00',drot,1)
> 		else:
> 			pass
> 	updateFile.close()
> 
Hi,

I am not sure about that, but I think you should use the fileinput module for that, like:

def modify5File():
    for line in fileinput.input(path-to-file, inplace=1):
        line = line.replace('+0.2000000000d+00', '0.678')
        sys.stdout.write(line)

This should replace every '+0.2000000000d+00' in the file with '0.678' .

Best regards

Michael