We have a sample .cfg file consist of key value pair. Based on user input, we need to update the value. I was thinking to update the value using configParser but file doesn't have any section (e.g. [My Section]). Based on the documentation it needs three values to set - section, key and value. Unfortunately, I will not be able to add any section marker, as this file is used by other tasks.
What would be the another way we can set the value based on key?
File example
some.status_file_mode = 1 # Some comment
some.example_time = 7200 # Some comment
As per the requirement, no change in the line. Spaces and comments needs to be same as is.
Use NamedTemporaryFile from the tempfile module it is not too hard to build a simple parser to update a file that looks like that:
Code:
def replace_key(filename, key, value):
with open(filename, 'rU') as f_in, tempfile.NamedTemporaryFile(
'w', dir=os.path.dirname(filename), delete=False) as f_out:
for line in f_in.readlines():
if line.startswith(key):
line = '='.join((line.split('=')[0], ' {}'.format(value)))
f_out.write(line)
# remove old version
os.unlink(filename)
# rename new version
os.rename(f_out.name, filename)
Test Code:
import os
import tempfile
replace_key('file1', 'some.example_time', 3)
Results:
some.status_file_mode = 1
some.example_time = 3
If you don't care about spacing, this works well for your case.
def replace_config(filename, key, value):
d = {}
with open(filename, "r+") as f:
for line in f:
k, v = line.split('=')
c = ""
try:
v, c = v.split('#')
except ValueError:
c = ""
d[k.strip()] = {'v': v.strip(), 'c': c.strip()}
f.seek(0)
f.truncate()
d[key]['v'] = value
for k, v in d.items():
if v["c"]:
text = "{} = {} # {}\n".format(k, v['v'], v['c'])
else:
text = "{} = {}\n".format(k, v['v'])
f.write(text)
replace_config('config.cfg', 'some.example_time', 3)
Related
I wanted to make a program that tracks the progress of our competition. I made a library containing our names as the key, and our wins as the value. I then made a JSON file to save the progress. But for some reason, when I re-run the program, it goes back to it's initial values and adds the new one; as if it was the first time I used the program.
Here is my code:
import os, json, sys
Numbers = {
"Peter" : 1,
"Drew" : 1,
}
def q1():
New_numbers = {}
q = input("Name? ")
if q not in Numbers:
Numbers[q] =1
with open("list.json", "w") as f:
json.dump(Numbers, f)
f.close()
with open("list.json", "r") as f:
New_numbers = json.load(f)
for key,value in New_numbers.items():
print(key, ":", value)
elif q in Numbers:
Numbers[q] += 1
with open("list.json", "w") as f:
json.dump(Numbers, f)
f.close()
with open("list.json", "r") as f:
New_numbers = json.load(f)
for key,value in New_numbers.items():
print(key, ":", value)
q1()
The first use, it works perfectly. However, as I've mentioned before, when I use it again, it loads the initial library; not the JSON file.
have a Dict with multiple values in a tuple.
newhost = {'newhost.com': ('1.oldhost.com',
'2.oldhost.com',
'3.oldhost.com',
'4.oldhost.com')
}
I wanna open a existing file and search for lines in this file that contains a value of the oldhosts. A file can have multiple Account Lines. In example
Account: 1.oldhost.com username
Account: someotherhost username
When the line with 1.oldhost.com or 2.oldhost.com or 3.oldhost.com and so on is found i wanna replace it with the key form the dict newhost.com.
Can anyone help me? Searched alot, but didnt find the right thing.
Regards
Maybe something like this could get you started
infile_name = 'some_file.txt'
# Open and read the incoming file
with open(infile_name, 'r') as infile:
text = infile.read()
# Cycle through the dictionary
for newhost, oldhost_list in host_dict.items():
# Cycle through each possible old host
for oldhost in oldhost_list:
text.replace(oldhost, newhost)
outfile_name = 'some_other_file.txt'
# Write to file
with open(outfile_name, 'w') as outfile:
outfile.write(text)
Not claiming this to be the best solution, but it should be a good start for you.
To easily find the new host for a given old host, you should convert your data structure:
# your current structure
new_hosts = {
'newhost-E.com': (
'1.oldhost-E.com',
'2.oldhost-E.com',
),
'newhost-A.com': (
'1.oldhost-A.com',
'2.oldhost-A.com',
'3.oldhost-A.com',
),
}
# my proposal
new_hosts_2 = {
v: k
for k, v_list in new_hosts.items()
for v in v_list}
print(new_hosts_2)
# {
# '1.oldhost-E.com': 'newhost-E.com',
# '2.oldhost-E.com': 'newhost-E.com',
# '1.oldhost-A.com': 'newhost-A.com',
# '2.oldhost-A.com': 'newhost-A.com',
# '3.oldhost-A.com': 'newhost-A.com',
# }
This does repeat the new host names (the values in new_hosts_2), but it will allow you to quickly look up given an old host name:
some_old_host = 'x.oldhost.com'
the corresponding_new_host = new_hosts_2[some_old_host]
Now you just need to:
read the lines of the file
find the old hostname in that line
lookup the corresponding new host in new_hosts_2
replace that value in the line
write the line to a new file
Maybe like this:
with open(file_name_1, 'r') as fr:
with open(file_name_2, 'w') as fw:
for line in fr:
line = line.strip()
if len(line) > 0:
# logic to find the start and end position of the old host
start_i = ?
end_i = ?
# get and replace, but only if its found in 'new_hosts_2'
old_host = line[start_i:end_i]
if old_host in new_hosts_2:
line = line[:start_i] + new_hosts_2[old_host] + line[end_i:]
fw.write(line + '\n')
Thank you for your tips. I came up with this now and it is working fine.
import fileinput
textfile = 'somefile.txt'
curhost = 'newhost.com'
hostlist = {curhost: ('1.oldhost.com',
'2.oldhost.com',
'3.oldhost.com')
}
new_hosts_2 = {
v: k
for k, v_list in hostlist.items()
for v in v_list}
for line in fileinput.input(textfile, inplace=True):
line = line.rstrip()
if not line:
continue
for f_key, f_value in new_hosts_2.items():
if f_key in line:
line = line.replace(f_key, f_value)
print line
I have code which runs but doesn't save anything to the text file?
def saving_multiple_scores():
with open(class_number) as file:
dic = {}
for line in file:
key, value = line.strip().split(':')
dic.setdefault(key, []).append(value)
file.write(dic)
with open(class_number, 'a') as file:
for key, value in dic.items():
file.write(key + ':' + ','.join(value) + '\n')
print(dic)
It should check if the name is already in the file, and if so: append a score
and if not then create a new list with the score.
However nothing is saving at all.
Python, IDLE V3.4.2
I am new to this so any help is appreciated
the first with is not working because the file is empty and the for loop iterates over lines in file
The default for mode for open (see https://docs.python.org/2/library/functions.html#open) is read only so file.write(dic) won't work
Expanding on Pawel’s suggestion, here is what you do to fix your code:
from collections import defaultdict
def saving_multiple_scores():
with open(class_number, 'r') as f: # don't use file
data = defaultdict(list)
for line in f:
line = line.strip()
if not line:
continue # skip over any blank lines in the file
key, value = line.split(':')
data[key.strip()].append(value.strip())
# file.write removed because we don't write in readmode
with open(class_number, 'a') as f:
# using 'a' mode will append the score lists
# to the end of the file
# to overwrite the file completely, use 'w'
for key, value in data.items():
line = '%s:%s\n' % (key, ','.join(value),)
f.write(line)
print '%s' % line,
Sample input file:
alice:1
alice:2
alice:3
bob:1
alice:4
bob:2
Sample output file:
alice:1
alice:2
alice:3
bob:1
alice:4
bob:2
bob:1,2
alice:1,2,3,4
I'm trying to implement a simple helper class to interact with java-properties files. Fiddling with multiline properties I encountered a problem, that I can not get solved, maybe you can?
The unittest in the class first writes a multiline-property spanning over two lines to the property-file, then re-reads it and checks for equality. That just works. Now, if i use the class to add a third line to the property, it re-reads it with additional backslashes that I can't explain.
Here is my code:
#!/usr/bin/env python3
# -*- coding=UTF-8 -*-
import codecs
import os, re
import fileinput
import unittest
class ConfigParser:
reProp = re.compile(r'^(?P<key>[\.\w]+)=(?P<value>.*?)(?P<ext>[\\]?)$')
rePropExt = re.compile(r'(?P<value>.*?)(?P<ext>[\\]?)$')
files = []
def __init__(self, pathes=[]):
for path in pathes:
if os.path.isfile(path):
self.files.append(path)
def getOptions(self):
result = {}
key = ''
val = ''
with fileinput.input(self.files, inplace=False) as fi:
for line in fi:
m = self.reProp.match(line.strip())
if m:
key = m.group('key')
val = m.group('value')
result[key] = val
else:
m = self.rePropExt.match(line.rstrip())
if m:
val = '\n'.join((val, m.group('value')))
result[key] = val
fi.close()
return result
def setOptions(self, updates={}):
options = self.getOptions()
options.update(updates)
with fileinput.input(self.files, inplace=True) as fi:
for line in fi:
m = self.reProp.match(line.strip())
if m:
key = m.group('key')
nval = options[key]
nval = nval.replace('\n', '\\\n')
print('{}={}'.format(key,nval))
fi.close()
class test(unittest.TestCase):
files = ['test.properties']
props = {'test.m.a' : 'Johnson\nTanaka'}
def setUp(self):
for file in self.files:
f = codecs.open(file, encoding='utf-8', mode='w')
for key in self.props.keys():
val = self.props[key]
val = re.sub('\n', '\\\n', val)
f.write(key + '=' + val)
f.close()
def teardown(self):
pass
def test_read(self):
c = configparser(self.files)
for file in self.files:
for key in self.props.keys():
result = c.getOptions()
self.assertEqual(result[key],self.props[key])
def test_write(self):
c = ConfigParser(self.files)
changes = {}
for key in self.props.keys():
changes[key] = self.change_value(self.props[key])
c.setOptions(changes)
result = c.getOptions()
print('changes: ')
print(changes)
print('result: ')
print(result)
for key in changes.keys():
self.assertEqual(result[key],changes[key],msg=key)
def change_value(self, value):
return 'Smith\nJohnson\nTanaka'
if __name__ == '__main__':
unittest.main()
Output of the testrun:
C:\pyt>propertyfileparser.py
changes:
{'test.m.a': 'Smith\nJohnson\nTanaka'}
result:
{'test.m.a': 'Smith\nJohnson\\\nTanaka'}
Any hints welcome...
Since you are adding a backslash in front of new-lines when you are writing, you have to also remove them when you are reading. Uncommenting the line that substitutes '\n' with '\\n' solves the problem, but I expect this also means the file syntax is incorrect.
This happens only with the second line break, because you separate the value into an "oval" and an "nval" where the "oval" is the first line, and the "nval" the rest, and you only do the substitution on the nval.
It's also overkill to use regexp replacing to replace something that isn't a regexp. You can use val.replace('\n', '\\n') instead.
I'd do this parser very differently. Well, first of all, I wouldn't do it at all, I'd use an existing parser, but if I did, I'd read the file, line by line, while handling the line continuation issue, so that I had exactly one value per item in a list. Then I'd parse each item into a key and a value with a regexp, and stick that into a dictionary.
You instead parse each line separately and join continuation lines to the values after parsing, which IMO is completely backwards.
I am parsing a config file I would like to get only the values which are file paths in the file
for example the config file has
apache.access = /var/log/apache2/access.log
apache.errors = /var/log/apache2/errors.log
I would like to get only '/var/log/apache2/access.log' and '/var/log/apache2/errors.log' from the
COMMENT_CHAR = '#'
OPTION_CHAR = '='
def parse_config(filename):
options = {}
f = open(filename)
for line in f:
if COMMENT_CHAR in line:
line, comment = line.split(COMMENT_CHAR, 1)
if OPTION_CHAR in line:
option, value = line.split(OPTION_CHAR, 1)
option = option.strip()
value = value.strip()
options[option] = value
f.close()
return options
I tried this but it gives all the options and values in the file
apache.access : /var/log/apache2/access.log
apache.errors : /var/log/apache2/errors.log
First you have to define, what is a file path (1. does it have to exist? 2. does it have to be creatable in an existing directory? 3. anything else?). This tests whether the given string is a path pointing to an existing dir/file:
import os
# ...
[v for v in options.itervalues() if os.path.exists(v)]
Regular expressions is what you need. Here is little example how it could look
import re
f = open("apache.log")
for line in f:
m = re.match("apache\.(access|errors)\s+=\s+(.+)", line)
if None != m:
print (m.group(2))
f.close()