import os, re
config_file = "jsm_gyro_config.txt"
#fptr = open(config, "w")
#text = "demo text"
#fptr.write(text)
#fptr.close()
file = open(config_file, 'r')
file-read = file.read()
for line in file-read:
if re.search(userinput, file-read):
x = re.search(userinput, file-read)
# iteminputted is what the user wants to replace
iteminputted = "ref"
startpostion = x.span[1] + 3
endpostion = startposition + len(iteminputted)
# Find out how to write to a specific location in a file that will finish this off
else:
print("Item not found")
This is what i've tried and here is my thought process as always any help is appreatated and please make it understandable for an idiot :(
To begin with, you should not use - in your variable declarations as it is actually an operator and will always be treated as such. It will attempt to subtract.
Here is the same code with that fixed and also with the input
import os, re
config_file = "jsm_gyro_config.txt"
#fptr = open(config, "w")
#text = "demo text"
#fptr.write(text)
#fptr.close()
file = open(config_file, 'r')
file_read = file.read()
file.close() # You should always close your files.
for line in file_read:
if re.search(userinput, file_read):
x = re.search(userinput, file_read)
# iteminputted is what the user wants to replace
iteminputted = input("Input what you would like to replace > ")
startpostion = x.span[1] + 3
endpostion = startposition + len(iteminputted)
# Find out how to write to a specific location in a file that will finish this off
else:
print("Item not found")
However your question is very unclear, I did the best I could.
Implement the function isWhiteLine(), which takes a string and returns TRUE if the
string contains only white space & tab characters. Program should read a file given as command-line argument, and print only non-blank lines onto the standard output.
import sys
def isWhiteLine(x):
return x.isspace()
file_name = sys.argv[1]
f = open(file_name, "r")
for i in f:
if (isWhiteLine(i) == False):
print(str(i).strip())
f.close()
The code below should support what you are looking for.
import sys
def print_non_empty_lines(file_name):
with open(file_name, 'r') as f:
lines = f.readlines()
for line in lines:
line = line.strip()
if line:
print(line)
if __name__ == "__main__":
if len(sys.argv) > 1:
print_non_empty_lines(sys.argv[1])
I created a notepad text document called "connections.txt". I need to have some initial information inside it, several lines of just URLs. Each URL has it's own line. I put that in manually. Then in my program I have a function that checks if a URL is in the file:
def checkfile(string):
datafile = file(f)
for line in datafile:
if string in line:
return True
return False
where f is declared at the beginning of the program:
f = "D:\connections.txt"
Then I tried to write to the document like this:
file = open(f, "w")
if checkfile(user) == False:
usernames.append(user)
file.write("\n")
file.write(user)
file.close()
but it hasn't really been working correctly..I'm not sure what's wrong..am I doing it wrong?
I want the information in the notepad document to stay there ACROSS runs of the program. I want it to build up.
Thanks.
EDIT: I found something wrong... It needs to be file = f, not datafile = file(f)
But the problem is... It clears the text document every time I rerun the program.
f = "D:\connections.txt"
usernames = []
def checkfile(string):
file = f
for line in file:
if string in line:
return True
print "True"
return False
print "False"
file = open(f, "w")
user = "aasdf"
if checkfile(user) == False:
usernames.append(user)
file.write("\n")
file.write(user)
file.close()
I was working with the file command incorrectly...here is the code that works.
f = "D:\connections.txt"
usernames = []
def checkfile(string):
datafile = file(f)
for line in datafile:
if string in line:
print "True"
return True
print "False"
return False
user = "asdf"
if checkfile(user) == False:
usernames.append(user)
with open(f, "a") as myfile:
myfile.write("\n")
myfile.write(user)
The code that checks for a specific URL is ok!
If the problem is not erasing everything:
To write to the document without erasing everything you have to use the .seek() method:
file = open("D:\connections.txt", "w")
# The .seek() method sets the cursor to the wanted position
# seek(offset, [whence]) where:
# offset = 2 is relative to the end of file
# read more here: http://docs.python.org/2/library/stdtypes.html?highlight=seek#file.seek
file.seek(2)
file.write("*The URL you want to write*")
Implemented on your code will be something like:
def checkfile(URL):
# your own function as it is...
if checkfile(URL) == False:
file = open("D:\connections.txt", "w")
file.seek(2)
file.write(URL)
file.close()
#!/usr/bin/env python`
import sys`
import binascii`
import string
sample = "foo.apples"
data_file = open("file1.py","r")
dat_file = open("file2.txt", "w")
for line in data_file:
if sample in line:
dat_file.writelines(line)
dat_file.close()`
When I do this I am able to find the string foo.apples. The problem is foo.apples is present in various lines in the python file. I want those lines which are inside a particular function. I need the lines within this def function.
Example:
def start():
foo.apples(a,b)
foo.apples(c,d) ... so on.
The following program finds defs and will append the sample string to the output file if the indentation remains within the def.
import re
sample = 'foo.apples'
data_file = open("file1.py", "r")
out_file = open("file2.txt", "w")
within_def = False
def_indent = 0
for line in data_file:
def_match = re.match(r'(\s*)def\s+start\s*\(', line) # EDIT: fixed regex
if def_match and not within_def:
within_def = True
def_indent = len(def_match.group(1))
elif within_def and re.match(r'\s{%s}\S' % def_indent, line):
within_def = False
if within_def and sample in line:
out_file.writelines(line)
out_file.close()
data_file.close()
Tested working on an example file1.py.
One, slightly off the beaten path approach to this would be to use the getsource method of the inspect module. Consider the following (theoretical) test1.py file:
class foo(object):
apples = 'granny_smith'
#classmethod
def new_apples(cls):
cls.apples = 'macintosh'
def start():
"""This is a pretty meaningless python function.
Attempts to run it will definitely result in an exception being thrown"""
print foo.apples
foo.apples = 3
[x for x in range(10)]
import bar as foo
Now you want to know about the start code:
import inspect
import test1 #assume it is somewhere that can be imported
print inspect.getsource(test1.start)
Ok, now we have only the source of that function. We can now parse through that:
for line in inspect.getsource(test1.start).splitlines():
if 'foo.apples' in line:
print line
There are some advantages here -- python does all the work of parsing out the function blocks when it imports the file. The downside though is that the file actually needs to be imported. Depending on where your files are coming from, this could introduce a HUGE security hole in your program -- You'll be running (potentially) "untrusted" code.
Here's a very non pythonic way, untested, but it should work.
sample = "foo.apples"
infile = open("file1.py", "r")
outfile = open("file2.txt", "w")
in_function = False
for line in infile.readlines():
if in_function:
if line[0] in(" ", "\t"):
if sample in line:
outfile.write(line)
else:
in_function = False
elif line.strip() == "def start():":
in_function = True
infile.close()
outfile.close()
I would suggest doing a function of this, which takes sample, the input file, and the function which we're supposed to search from as it's parameters. It would then return a list or tuple of all the lines that had the text in them.
def findFromFile(file, word, function):
in_function = False
matches = []
infile = open(file, "r")
for line in infile.readlines():
if in_function:
if line[0] in(" ", "\t"):
if word in line:
matches.append(line)
else:
in_function = False
elif line.strip() == "def %s():"%function:
in_function = True
infile.close()
return matches
I want to learn Python so I started writing my first program which is a phone book directory.
It has the options to add a name and phone number, remove numbers, and search for them.
Ive been stuck on the remove part for about 2 days now and just can't get it working correctly. I've been in the Python IRC and everything, but haven't been able to figure it out.
Basically, my program stores the numbers to a list in a file. I cannot figure out how to remove a particular line in the file but keep the rest of the file intact. Can someone please help me with this?
Some people have advised that it will be easier to do if I create a temp file, remove the line, then copy the remaining lines from the original file over to the temp file. Then write over the original file over with the temp file. So I have been trying this...
if ui == 'remove':
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt', 'r') # original phone number listing
f1 = open('codilist.tmp', 'a') # open a tmp file
for line in f:
if line.strip() != coname.strip():
for line in f:
f1.write(line)
break # WILL LATER OVERWRITE THE codilist.txt WITH THE TMP FILE
else:
f1.write(line)
else:
print 'Error: That company is not listed.'
f1.close()
f.close()
continue
I assume your file contains something like <name><whitespace><number> on each line? If that's the case, you could use something like this for your if statement (error handling not included!):
name, num = line.strip().split()
if name != coname.strip():
# write to file
Suggestion:
Unless there is some specific reason for you to use a custom format, the file format json is quite good for this kind of task. Also note the use of the 'with' statement in these examples, which saves you having to explicitly close the file.
To write the information:
import json
# Somehow build a dict of {coname: num,...}
info = {'companyA': '0123456789', 'companyB': '0987654321'}
with open('codilist.txt', 'w') as f:
json.dump(info, f, indent=4) # Using indent for prettier files
To read/amend the file:
import json
with open('codilist.txt', 'r+') as f:
info = json.load(f)
# Remove coname
if coname in info:
info.pop(coname)
else:
print 'No record exists for ' + coname
# Add 'companyC'
info['companyC'] = '0112233445'
# Write back to file
json.dump(info, f, indent=4)
You'll need python2.6 or later for these examples. If you're on 2.5, you'll need these imports:
import simplejson as json
from __future__ import with_statement
Hope that helps!
Here is a pretty extensively rewritten version:
all the phone data is wrapped into a Phonebook class; data is kept in memory (instead of being saved and reloaded for every call)
it uses the csv module to load and save data
individual actions are turned into short functions or methods (instead of One Big Block of Code)
commands are abstracted into a function-dispatch dictionary (instead of a cascade of if/then tests)
This should be much easier to understand and maintain.
import csv
def show_help():
print('\n'.join([
"Commands:",
" help shows this screen",
" load [file] loads the phonebook (file name is optional)",
" save [file] saves the phonebook (file name is optional)",
" add {name} {number} adds an entry to the phonebook",
" remove {name} removes an entry from the phonebook",
" search {name} displays matching entries",
" list show all entries",
" quit exits the program"
]))
def getparam(val, prompt):
if val is None:
return raw_input(prompt).strip()
else:
return val
class Phonebook(object):
def __init__(self, fname):
self.fname = fname
self.data = []
self.load()
def load(self, fname=None):
if fname is None:
fname = self.fname
try:
with open(fname, 'rb') as inf:
self.data = list(csv.reader(inf))
print("Phonebook loaded")
except IOError:
print("Couldn't open '{}'".format(fname))
def save(self, fname=None):
if fname is None:
fname = self.fname
with open(fname, 'wb') as outf:
csv.writer(outf).writerows(self.data)
print("Phonebook saved")
def add(self, name=None, number=None):
name = getparam(name, 'Company name? ')
number = getparam(number, 'Company number? ')
self.data.append([name,number])
print("Company added")
def remove(self, name=None):
name = getparam(name, 'Company name? ')
before = len(self.data)
self.data = [d for d in self.data if d[0] != name]
after = len(self.data)
print("Deleted {} entries".format(before-after))
def search(self, name=None):
name = getparam(name, 'Company name? ')
found = 0
for c,n in self.data:
if c.startswith(name):
found += 1
print("{:<20} {:<15}".format(c,n))
print("Found {} entries".format(found))
def list(self):
for c,n in self.data:
print("{:<20} {:<15}".format(c,n))
print("Listed {} entries".format(len(self.data)))
def main():
pb = Phonebook('phonebook.csv')
commands = {
'help': show_help,
'load': pb.load,
'save': pb.save,
'add': pb.add,
'remove': pb.remove,
'search': pb.search,
'list': pb.list
}
goodbyes = set(['quit','bye','exit'])
while True:
# get user input
inp = raw_input("#> ").split()
# if something was typed in
if inp:
# first word entered is the command; anything after that is a parameter
cmd,args = inp[0],inp[1:]
if cmd in goodbyes:
# exit the program (can't be delegated to a function)
print 'Goodbye.'
break
elif cmd in commands:
# "I know how to do this..."
try:
# call the appropriate function, and pass any parameters
commands[cmd](*args)
except TypeError:
print("Wrong number of arguments (type 'help' for commands)")
else:
print("I didn't understand that (type 'help' for commands)")
if __name__=="__main__":
main()
Something simple like this will read all of f, and write out all the lines that don't match:
for line in f:
if line.strip() != coname.strip():
f1.write(line)
Ned's answer looks like it should work. If you haven't tried this already, you can set python's interactive debugger above the line in question. Then you can print out the values of line.strip() and coname.strip() to verify you are comparing apples to apples.
for line in f:
import pdb
pdb.set_trace()
if line.strip() != coname.strip():
f1.write(line)
Here's a list of pdb commands.
You probably don't want to open the temp file in append ('a') mode:
f1 = open('codilist.tmp', 'a') # open a tmp file
also, be aware that
for line in f:
...
f1.write(line)
will write everything to the file without newlines.
The basic structure you want is:
for line in myfile:
if not <line-matches-company>:
tmpfile.write(line + '\n') # or print >>tmpfile, line
you'll have to implement <line-matches-company> (there isn't enough information in the question to know what it should be -- perhaps if you showed a couple of lines from your data file..?)
I got this working...
if ui == 'remove':
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt')
tmpfile = open('codilist.tmp', 'w')
for line in f:
if coname in line:
print coname + ' has been removed.'
else:
tmpfile.write(line)
f.close()
tmpfile.close()
os.rename('codilist.tmp', 'codilist.txt')
continue