Develop Reference

Python conditional statement based on text file string

Noob question here. I'm scheduling a cron job for a Python script for every 2 hours, but I want the script to stop running after 48 hours, which is not a feature of cron. To work around this, I'm recording the number of executions at the end of the script in a text file using a tally mark x and opening the text file at the beginning of the script to only run if the count is less than n.
However, my script seems to always run regardless of the conditions. Here's an example of what I've tried:
with open("curl-output.txt", "a+") as myfile:
data = myfile.read()
finalrun = "xxxxx"
if data != finalrun:
[CURL CODE]
with open("curl-output.txt", "a") as text_file:
text_file.write("x")
text_file.close()
I think I'm missing something simple here. Please advise if there is a better way of achieving this. Thanks in advance.

The problem with your original code is that you're opening the file in a+ mode, which seems to set the seek position to the end of the file (try print(data) right after you read the file). If you use r instead, it works. (I'm not sure that's how it's supposed to be. This answer states it should write at the end, but read from the beginning. The documentation isn't terribly clear).
Some suggestions: Instead of comparing against the "xxxxx" string, you could just check the length of the data (if len(data) < 5). Or alternatively, as was suggested, use pickle to store a number, which might look like this:
import pickle
try:
with open("curl-output.txt", "rb") as myfile:
num = pickle.load(myfile)
except FileNotFoundError:
num = 0
if num < 5:
do_curl_stuff()
num += 1
with open("curl-output.txt", "wb") as myfile:
pickle.dump(num, myfile)
Two more things concerning your original code: You're making the first with block bigger than it needs to be. Once you've read the string into data, you don't need the file object anymore, so you can remove one level of indentation from everything except data = myfile.read().
Also, you don't need to close text_file manually. with will do that for you (that's the point).

Sounds more for a job scheduling with at command?
See http://www.ibm.com/developerworks/library/l-job-scheduling/ for different job scheduling mechanisms.

The first bug that is immediately obvious to me is that you are appending to the file even if data == finalrun. So when data == finalrun, you don't run curl but you do append another 'x' to the file. On the next run, data will be not equal to finalrun again so it will continue to execute the curl code.
The solution is of course to nest the code that appends to the file under the if statement.

Well there probably is an end of line jump \n character which makes that your file will contain something like xx\n and not simply xx. Probably this is why your condition does not work :)
EDIT
What happens if through the python command line you type
open('filename.txt', 'r').read() # where filename is the name of your file
you will be able to see whether there is an \n or not

Try using this condition along with if clause instead.
if data.count('x')==24
data string may contain extraneous data line new line characters. Check repr(data) to see if it actually a 24 x's.

Python write to a file r

I am trying to write some basic lines to a text file using Python 3.3.2 (complete beginner here).Not sure why a number returns after the write command line. The number seems to be the length of the string. The string does get stored into the new text file and everything else seems to be okay.
Also :
>>> f=open('testfile.txt','w')
>>> f.write('this is line 1\n')
15
So, the number '15'.. not sure what it means. Every line I write would return an integer.

From docs:
f.write(string) writes the contents of string to the file, returning
the number of characters written.

A better way to write this would be
print('this is line 1', file=f)
Because it is more flexible (it takes any input type, not just str) and it automatically adds the newline character. As an added bonus, it won't echo anything in the python shell.

How can I incorporate a text file into the body of my Python script?

Currently, my code is reading an external text file, using:
text_file = open("file.txt", 'r', 0)
my_list = []
for line in text_file
my_list.append(line.strip().lower())
return my_list
I would like to send my code to a friend without having to send a separate text file. So I am looking for a way of incorporating the content of the text file into my code.
How can I achieve this?
If I convert the text file into list format ([a, b, c, ...]) inside MS notepad using replace function, and then try to copy & paste list into Python IDE (I'm using IDLE), the process is hellishly memory intensive: IDLE tries to string out everything to the right in one line (i.e. no word wrap), and it never ends.

I'm not totally sure what you're asking, but if I'm guessing what you mean correctly, you could do this:
my_list = ['line1', 'line2']
Where each is a line from your text file.

Just put all the file contents into ONE MASSIVE string:
with open('path/to/my/txt/file') as f:
file_contents = f.read()
So now, your friend can do:
for line in file_contents.split('\n'):
#code
which is equivalent to
with open('path/to/file') as f:
for line in f:
#code
Hope this helps

I would suggest
assign the contents of the file to a variable in another py file
read the value by importing it in you program
that way the py file will be converted to pyc (send that), or py2exe will take care of it..
and would not allow your friend to mess with the contents...

You could also do something like:
my_file_contents = """file_contents_including_newlines"""
for line in my_file_contents.split('\n'): # Assuming UNIX line ending, else split '\r\n'
*do something with "line" variable*
Note the use of triple quotes around the text to be sent. This would work for non-binary data.

Write strings to another file

The Problem - Update:
I could get the script to print out but had a hard time trying to figure out a way to put the stdout into a file instead of on a screen. the below script worked on printing results to the screen. I posted the solution right after this code, scroll to the [ solution ] at the bottom.
First post:
I'm using Python 2.7.3. I am trying to extract the last words of a text file after the colon (:) and write them into another txt file. So far I am able to print the results on the screen and it works perfectly, but when I try to write the results to a new file it gives me str has no attribute write/writeline. Here it the code snippet:
# the txt file I'm trying to extract last words from and write strings into a file
#Hello:there:buddy
#How:areyou:doing
#I:amFine:thanks
#thats:good:I:guess
x = raw_input("Enter the full path + file name + file extension you wish to use: ")
def ripple(x):
with open(x) as file:
for line in file:
for word in line.split():
if ':' in word:
try:
print word.split(':')[-1]
except (IndexError):
pass
ripple(x)
The code above works perfectly when printing to the screen. However I have spent hours reading Python's documentation and can't seem to find a way to have the results written to a file. I know how to open a file and write to it with writeline, readline, etc, but it doesn't seem to work with strings.
Any suggestions on how to achieve this?
PS: I didn't add the code that caused the write error, because I figured this would be easier to look at.
End of First Post
The Solution - Update:
Managed to get python to extract and save it into another file with the code below.
The Code:
inputFile = open ('c:/folder/Thefile.txt', 'r')
outputFile = open ('c:/folder/ExtractedFile.txt', 'w')
tempStore = outputFile
for line in inputFile:
for word in line.split():
if ':' in word:
splitting = word.split(':')[-1]
tempStore.writelines(splitting +'\n')
print splitting
inputFile.close()
outputFile.close()
Update:
checkout droogans code over mine, it was more efficient.

Try this:
with open('workfile', 'w') as f:
f.write(word.split(':')[-1] + '\n')
If you really want to use the print method, you can:
from __future__ import print_function
print("hi there", file=f)
according to Correct way to write line to file in Python. You should add the __future__ import if you are using python 2, if you are using python 3 it's already there.

I think your question is good, and when you're done, you should head over to code review and get your code looked at for other things I've noticed:
# the txt file I'm trying to extract last words from and write strings into a file
#Hello:there:buddy
#How:areyou:doing
#I:amFine:thanks
#thats:good:I:guess
First off, thanks for putting example file contents at the top of your question.
x = raw_input("Enter the full path + file name + file extension you wish to use: ")
I don't think this part is neccessary. You can just create a better parameter for ripple than x. I think file_loc is a pretty standard one.
def ripple(x):
with open(x) as file:
With open, you are able to mark the operation happening to the file. I also like to name my file object according to its job. In other words, with open(file_loc, 'r') as r: reminds me that r.foo is going to be my file that is being read from.
for line in file:
for word in line.split():
if ':' in word:
First off, your for word in line.split() statement does nothing but put the "Hello:there:buddy" string into a list: ["Hello:there:buddy"]. A better idea would be to pass split an argument, which does more or less what you're trying to do here. For example, "Hello:there:buddy".split(":") would output ['Hello', 'there', 'buddy'], making your search for colons an accomplished task.
try:
print word.split(':')[-1]
except (IndexError):
pass
Another advantage is that you won't need to check for an IndexError, since you'll have, at least, an empty string, which when split, comes back as an empty string. In other words, it'll write nothing for that line.
ripple(x)
For ripple(x), you would instead call ripple('/home/user/sometext.txt').
So, try looking over this, and explore code review. There's a guy named Winston who does really awesome work with Python and self-described newbies. I always pick up new tricks from that guy.
Here is my take on it, re-written out:
import os #for renaming the output file
def ripple(file_loc='/typical/location/while/developing.txt'):
outfile = "output.".join(os.path.basename(file_loc).split('.'))
with open(outfile, 'w') as w:
lines = open(file_loc, 'r').readlines() #everything is one giant list
w.write('\n'.join([line.split(':')[-1] for line in lines]))
ripple()
Try breaking this down, line by line, and changing things around. It's pretty condensed, but once you pick up comprehensions and using lists, it'll be more natural to read code this way.

You are trying to call .write() on a string object.
You either got your arguments mixed up (you'll need to call fileobject.write(yourdata), not yourdata.write(fileobject)) or you accidentally re-used the same variable for both your open destination file object and storing a string.

How to Find a String in a Text File And Replace Each Time With User Input in a Python Script?

I am new to python so excuse my ignorance.
Currently, I have a text file with some words marked as <>.
My goal is to essentially build a script which runs through a text file with such marked words. Each time the script finds such a word, it would ask the user for what it wants to replace it with.
For example, if I had a text file:
Today was a <<feeling>> day.
The script would run through the text file so the output would be:
Running script...
feeling? great
Script finished.
And generate a text file which would say:
Today was a great day.
Advice?
Edit: Thanks for the great advice! I have made a script that works for the most part like I wanted. Just one thing. Now I am working on if I have multiple variables with the same name (for instance, "I am <>. Bob is also <>.") the script would only prompt, feeling?, once and fill in all the variables with the same name.
Thanks so much for your help again.

import re
with open('in.txt') as infile:
text = infile.read()
search = re.compile('<<([^>]*)>>')
text = search.sub(lambda m: raw_input(m.group(1) + '? '), text)
with open('out.txt', 'w') as outfile:
outfile.write(text)

Basically the same solution as that offerred by #phihag, but in script form
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import argparse
import re
from os import path
pattern = '<<([^>]*)>>'
def user_replace(match):
return raw_input('%s? ' % match.group(1))
def main():
parser = argparse.ArgumentParser()
parser.add_argument('infile', type=argparse.FileType('r'))
parser.add_argument('outfile', type=argparse.FileType('w'))
args = parser.parse_args()
matcher = re.compile(pattern)
for line in args.infile:
new_line = matcher.sub(user_replace, line)
args.outfile.write(new_line)
args.infile.close()
args.outfile.close()
if __name__ == '__main__':
main()
Usage: python script.py input.txt output.txt
Note that this script does not account for non-ascii file encoding.

To open a file and loop through it:
Use raw_input to get input from user
Now, put this together and update you question if you run into problems :-)

I understand you want advice on how to structure your script, right? Here's what I would do:
Read the file at once and close it (I personally don't like to have open file objects, especially if my filesystem is remote).
Use a regular expression (phihag has suggested one in his answer, so I won't repeat it) to match the pattern of your placeholders. Find all of your placeholders and store them in a dictionary as keys.
For each word in the dictionary, ask the user with raw_input (not just input). And store them as values in the dictionary.
When done, parse your text substituting any instance of a given placeholder (key) with the user word (value). This is also done with regex.
The reason for using a dictionary is that a given placeholder could occur more than once and you probably don't want to make the user repeat the entry over and over again...

Try something like this
lines = []
with open(myfile, "r") as infile:
lines = infile.readlines()
outlines = []
for line in lines:
index = line.find("<<")
if index > 0:
word = line[index+2:line.find(">>")]
input = raw_input(word+"? ")
outlines.append(line.replace("<<"+word+">>", input))
else:
outlines.append(line)
with open(outfile, "w") as output:
for line in outlines:
outfile.write(line)
Disclaimer: I haven't actually run this, so it might not work, but it looks about right and is similar to something I've done in the past.
How it works:
It parses the file in as a list where each element is one line of the file.
It builds the output list of lines. It iterates through the lines in the input, checking if the string << exist. If it does, it rips out the word inside the << and >> brackets, using it as the question for a raw_input query. It takes the input from that query and replaces the value inside the arrows (and the arrows) with the input. It then appends this value to the list. If it didn't see the arrows it simply appended the line.
After running through all the lines, it writes them to the output file. You can make this whatever file you want.
Some issues:
As written, this will work for only one arrow statement per line. So if you had <<firstname>> <<lastname>> on the same line it would ignore the lastname portion. Fixing this wouldn't be too hard to implement - you could place a while loop using the index > 0 statement and holding the lines inside that if statement. Just remember to update the index again if you do that!
It iterates through the list three times. You could likely reduce this to two, but if you have a small text file this shouldn't be a huge problem.
It could be sensitive to encoding - I'm not entirely sure about that however. Worst case there you need to cast as a string.
Edit: Moved the +2 to fix the broken if statement.