Programming Forums > Script Programming > Python

SaturN · Jun 9th, 2005, 2:51 PM

Does anyone know how to remove a choosen line in a dat file?
i want to search for a word in the file, and then remove it if it exists, otherwise just return a message, saying not found? any ideas anyone?

EverLearning · Jun 9th, 2005, 3:33 PM

Seems like there's del keyword in Python:

(Toggle Plain Text)

FileList = file("file.dat", "r").readlines()
del FileList[line-to-delete]
file("file.dat", "w").writelines(FileList)

line-to-delete is the number of the line in file or list [0-n].

SaturN · Jun 9th, 2005, 3:42 PM

How do i find the line number returned from the searched word then?? lol
thanks for that

EverLearning · Jun 9th, 2005, 4:27 PM

To return line# where the word is:
look up .filelineno() and .find()

EverLearning · Jun 9th, 2005, 7:03 PM

Ok, it was bugging me, so i did it over the break. Here's my vesion of "find a line where the search_word is" and it works:

(Toggle Plain Text)

#!usr/bin/env python

import sys, fileinput

for line in fileinput.input():
        if line.find("search_word") >= 0:
                print "line is %d" % (fileinput.filelineno())

call it as
$ python script.py text.dat

SaturN · Jun 10th, 2005, 1:51 PM

Don't Work
�_�
hehe, pulls up a nice attribute error

SaturN · Jun 10th, 2005, 2:08 PM

don't worry sorted it.
are your indentions meant to be so far out?? mine works and they are set as there meant to!!

(Toggle Plain Text)

import sys, fileinput
search = raw_input("Search: ")
for line in fileinput.input("text.txt"):
    if line.find(search) >= 0:
        print "line is %d" % (fileinput.filelineno())

CrAzY_J · Jun 10th, 2005, 2:10 PM

Quote:

Originally Posted by SaturN

Don't Work
�_�
hehe, pulls up a nice attribute error

Well he basicly already gave you enough information to do this on your own.

look up how to use the .find() function and try to make the code yourself (using the method in the first example should help)

EverLearning · Jun 10th, 2005, 2:20 PM

Quote:

Originally Posted by SaturN

don't worry sorted it.
are your indentions meant to be so far out?? mine works and they are set as there meant to!!

Yes, it has to be a tab, at least for my interpreter.

SaturN · Jun 10th, 2005, 2:37 PM

that was all 2 tabs..
i have sorted it all anyway

Jun 9th, 2005, 2:51 PM	#1
SaturN Programmer Join Date: Apr 2005 Location: Uk Posts: 68 Rep Power: 4	Remove line from dat file Does anyone know how to remove a choosen line in a dat file? i want to search for a word in the file, and then remove it if it exists, otherwise just return a message, saying not found? any ideas anyone?

Jun 9th, 2005, 3:33 PM	#2
EverLearning Hobbyist Programmer Join Date: May 2005 Location: Indiana Posts: 130 Rep Power: 4	Seems like there's del keyword in Python: (Toggle Plain Text) FileList = file("file.dat", "r").readlines() del FileList[line-to-delete] file("file.dat", "w").writelines(FileList) FileList = file("file.dat", "r").readlines() del FileList[line-to-delete] file("file.dat", "w").writelines(FileList) line-to-delete is the number of the line in file or list [0-n]. __________________ got math? yumm... "All men by nature desire to know" -Aristotle, Metaphysics Last edited by EverLearning; Jun 9th, 2005 at 3:38 PM.

Jun 9th, 2005, 4:27 PM	#4
EverLearning Hobbyist Programmer Join Date: May 2005 Location: Indiana Posts: 130 Rep Power: 4	To return line# where the word is: look up .filelineno() and .find() __________________ got math? yumm... "All men by nature desire to know" -Aristotle, Metaphysics Last edited by EverLearning; Jun 9th, 2005 at 5:01 PM.

Jun 9th, 2005, 7:03 PM	#5
EverLearning Hobbyist Programmer Join Date: May 2005 Location: Indiana Posts: 130 Rep Power: 4	Ok, it was bugging me, so i did it over the break. Here's my vesion of "find a line where the search_word is" and it works: (Toggle Plain Text) #!usr/bin/env python import sys, fileinput for line in fileinput.input(): if line.find("search_word") >= 0: print "line is %d" % (fileinput.filelineno()) #!usr/bin/env python import sys, fileinput for line in fileinput.input(): if line.find("search_word") >= 0: print "line is %d" % (fileinput.filelineno()) call it as $ python script.py text.dat __________________ got math? yumm... "All men by nature desire to know" -Aristotle, Metaphysics Last edited by EverLearning; Jun 9th, 2005 at 7:05 PM.

Jun 10th, 2005, 2:08 PM	#7
SaturN Programmer Join Date: Apr 2005 Location: Uk Posts: 68 Rep Power: 4	don't worry sorted it. are your indentions meant to be so far out?? mine works and they are set as there meant to!! (Toggle Plain Text) import sys, fileinput search = raw_input("Search: ") for line in fileinput.input("text.txt"): if line.find(search) >= 0: print "line is %d" % (fileinput.filelineno()) import sys, fileinput search = raw_input("Search: ") for line in fileinput.input("text.txt"): if line.find(search) >= 0: print "line is %d" % (fileinput.filelineno())

Jun 9th, 2005, 3:42 PM	#3
SaturN Programmer Join Date: Apr 2005 Location: Uk Posts: 68 Rep Power: 4	How do i find the line number returned from the searched word then?? lol thanks for that

Jun 10th, 2005, 1:51 PM	#6
SaturN Programmer Join Date: Apr 2005 Location: Uk Posts: 68 Rep Power: 4	Don't Work �_� hehe, pulls up a nice attribute error

Jun 10th, 2005, 2:37 PM	#10
SaturN Programmer Join Date: Apr 2005 Location: Uk Posts: 68 Rep Power: 4	that was all 2 tabs.. i have sorted it all anyway

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Programming Forums > Script Programming > Python

Remove line from dat file