File is created but cannot be written in Python

Question

I am trying to write some results I get from a function for a range but I don't understand why the file is empty. The function is working fine because I can see the results in the console when I use print. First, I'm creating the file which is working because it is created; the output file name is taken from a string, and that part is working too. So the following creates the file in the given path:

report_strategy = open(output_path+strategy.partition("strategy(")[2].partition(",")[0]+".txt", "w")

it creates a text file with the name taken from a string named "strategy", for example:

strategy = "strategy(abstraction,Ent_parent)"

a file called "abstraction.txt" is created in the output path folder. So far so good. But I can't get to write anything to this file. I have a range of a few integers

maps = (175,178,185)

This is the function:

def strategy_count(map_path,map_id)

The following loop does the counting for each item in the range "maps" to return an integer:

for i in maps: report_strategy.write(str(i), ",", str(strategy_count(maps_path,str(i))))

and the file is closed at the end:

report_strategy.close()

Now the following:

 for i in maps: print str(i), "," , strategy_count(maps_path,str(i))

does give me what I want in the console:

175 , 3 178 , 0 185 , 1

What am I missing?! The function works, the file is created. I see the output in the console as I want, but I can't write the same thing in the file. And of course, I close the file.

This is a part of a program that reads text files (actually Prolog files) and runs an Answer Set Programming solver called Clingo. Then the output is read to find instances of occurring strategies (a series of actions with specific rules). The whole code:

import pmaps import strategies import generalization # select the strategy to count: strategy = strategies.abstraction_strategy import subprocess def strategy_count(path,name): p=subprocess.Popen([pmaps.clingo_path,"0",""], stdout=subprocess.PIPE,stderr=subprocess.STDOUT,stdin=subprocess.PIPE) # ## write input facts and rules to clingo with open(path+name+".txt","r") as source: for line in source: p.stdin.write(line) source.close() # some generalization rules added p.stdin.write(generalization.parent_of) p.stdin.write(generalization.chain_parent_of) # add the strategy p.stdin.write(strategy) p.stdin.write("#hide.") p.stdin.write("#show strategy(_,_).") #p.stdin.write("#show parent_of(_,_,_).") # close the input to clingo p.stdin.close() lines = [] for line in p.stdout.readlines(): lines.append(line) counter=0 for line in lines: if line.startswith('Answer'): answer = lines[counter+1] break if line.startswith('UNSATISFIABLE'): answer = '' break counter+=1 strategies = answer.count('strategy') return strategies # select which data set (from the "pmaps" file) to count strategies for: report_strategy = open(pmaps.hw3_output_path+strategy.partition("strategy(")[2].partition(",")[0]+".txt", "w") for i in pmaps.pmaps_hw3_fall14: report_strategy.write(str(i), ",", str(strategy_count(pmaps.path_hw3_fall14,str(i)))) report_strategy.close() # the following is for testing the code. It is working and there is the right output in the console #for i in pmaps.pmaps_hw3_fall14: # print str(i), "," , strategy_count(pmaps.path_hw3_fall14,str(i))

@Kevin I updated the post and put in all the code for this file. It reads a couple of other files (the first three imports), which basically store some path names and Prolog rules in text. — mdinar
– mdinar, Commented Sep 29, 2014 at 19:11

user2357112 · Accepted Answer · 2014-09-29 19:27:52Z

1

write takes one argument, which must be a string. It doesn't take multiple arguments like print, and it doesn't add a line terminator.

If you want the behavior of print, there's a "print to file" option:

print >>whateverfile, stuff, to, print

Looks weird, doesn't it? The function version of print, active by default in Python 3 and enabled with from __future__ import print_function in Python 2, has nicer syntax for it:

print(stuff, to, print, out=whateverfile)

edited Sep 29, 2014 at 19:27

answered Sep 29, 2014 at 19:14

user2357112

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4 Comments

tdelaney Over a year ago

It raises an exception, so either the for loop doesn't run or OP is missing an important detail.

user2357112 Over a year ago

@tdelaney: There was an s* in the PyArg_ParseTuple call that I wasn't familiar with, and I thought that might be attempting to read multiple arguments, but it turns out that format specifier reads one argument and fills a buffer.

mdinar Over a year ago

@user2357112 How do I get rid of the mess in the console? It wasn't used to be there. I used to get results directly from the console, but know it is buried under a pile of runtime log: # cleanup[2] numpy.polynomial.hermite # cleanup[2] numpy.polynomial.polynomial # cleanup[2] numpy.core._dotblas # cleanup[2] numpy.testing.nosetester # cleanup[2] time ....

user2357112 Over a year ago

If you have more questions, post a new question (but look for solutions yourself first).

mdinar · Accepted Answer · 2014-09-29 19:38:16Z

The problem was with the write which as @user2357112 mentioned takes only one argument. The solution could also be joining the strings with + or join():

for i in maps: report.write(str(i)+ ","+str(strategy_count(pmaps.path_hw3_fall14,str(i)))+"\n")

@user2357112 your answer might have the advantage of knowing if your test debug in the console produces the write answer, you just need to write that. Thanks.

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