I am trying to parse in a .lis file into python to perform further analysis on the data but every time I get the following error,
<_io.TextIOWrapper name='Data.lis' mode='r' encoding='cp1252'>
I am parsing in the file with the standard command,
open(fileName)
Is there a certain package I need to install or is my parsing method incorrect?
What you got as an output doesn't appear to be an error, it is just telling you that python opened the file, and you have a file type object now.
Further, the operation you performed only got you part of the way. When reading a file, you need to:
Open the file
Store it as a variable (usually)
Read the variable a line at a time
Parse the result of your reading
Close the file
I usually start by trying to open the file in a program like Notepad++. That way I can get an idea of what I am trying to parse.
Let's walk through an example:
filename = 'myfile.lis'
with open(filename) as f:
for line in f:
print(line)
The code above opens the .lis file, and then prints the file to the console one line at a time. The with statement ensure that the file gets closed after we're done.
However, you could just as well replace the print() command with a parse() command of your own choosing:
def parse(input_line):
if 'text' in input_line:
print('I found \'text\' in line \'{}\''.format(input_line))
Hopefully that will get you started. If you are able to provide more detail about what the contents of your .lis file is, or what you are looking to extract from that file, I'm sure many around here can provide better guidance.
Related
so I had an exercise asking to write to a file (using newlines) and then open it in reading mode. I did exactly that and the console outputs the right result. What happened was that I tried to do it within the 'w' mode code block and the console outputs nothing.
For example:
with open('test.txt', 'w') as wf:
nicknames = ["Big Tuna", "Prison Mike", "Booster Seat"]
wf.write('\n'.join(nicknames))
with open('test.txt', 'r') as rf:
print(rf.read())
I understand that the program only closes the file after the with statement, but I need clarification on my understanding of what's happening here.
So, what I understood so far is that the program first creates the test.txt file (test.txt did not exist in my file path) and then proceeds to convert and write the given contents into the test.txt file. After that, the nested with tries to open a file named test.txt in reading mode, but the console will not output anything because the program is trying to open a file that is already opened, that's why it cannot read into an already opened file.
Please correct me if I'm misunderstood the above because I am unsure whether or not I've understood it correctly, thank you.
That’s not what’s happening. Unix systems, at least, will happily let you open a file multiple times.
However, Python’s IO is buffered by default. You need to flush the data you’ve written out to the file before you can read the data from it. See https://docs.python.org/3/library/io.html#io.IOBase.flush for more information about this. (Summary: put wf.flush() after the wf.write(…) call and before attempting to read from it.
I am in an intro class and I've been looking for an answer for hours but I can't find one. My assignment is to use a txt. file and the list in it as an address book and whenever I call my menu() function after closing the file it doesn't run right it just is blank, I've printed "H" in places throughout the program to find where the logic error is and I've singled it down to after I close the file on line 47, If anybody would be able to help me it would be greatly appreciated and I'm a noob so roast my code as much as you like.my code
How are you opening the file right now? You may be opening the file in a write mode that overwrites prior content, if so I would suggest using open in the following form:
with open("demofile.txt", "r") as file:
# Do things with file such as reading the lines
lines = file.readlines()
...
This way the file will be open in read-only mode
Your code while open the file may throw some error and thus ending the try statement. Try using with statement or raise the error on except to track where's the error.
The code below is meant to find any xls or csv file used in a process. The .log file contains full paths with extensions and definitely contains multiple values with "xls" or "csv". However, Python can't find anything...Any idea? The weird thing is when I copy the content of the log file and paste it to another notepad file and save it as log, it works then...
infile=r"C:\Users\me\Desktop\test.log"
important=[]
keep_words=["xls","csv"]
with open(infile,'r') as f:
for line in f:
for word in keep_words:
if word in line:
important.append(line)
print(important)
I was able to figure it out...encoding issue...
with io.open(infile,encoding='utf16') as f:
You must change the line
for line in f:
to
for line in f.readlines():
You made the python search in the bytes opened file, not in his content, even in his lines (in a list, just like the readlines method);
I hope I was able to help (sorry about my bad English).
I am a beginner, writing a python script in which I need it to create a file that I can write information to. However, I am having problems getting it to create a new, not previously existing file.
for example, I have:
file = open(coordinates.kml, 'w')
which it proceeds to tell me:
nameerror: name 'coordinates' is not defined.
Of course it isn't defined, I'm trying to make that file.
Everything I read on creating a new file says to take this route, but it simply will not allow me. What am I doing wrong?
I even tried to flat out define it...
file = coordinates.kml
file_open = open(file, 'w')
... and essentially got the same result.
You need to pass coordinates.kml as a string, so place them in quotes (single or double is fine).
file = open("coordinates.kml", "w")
In addition to the above answer,
If you want to create a file in the same path, then no problem or else you need to specify the path as well in the quotes.
But surely opening a file with read permission will throw an error as you are trying to access an nonexistent file.
To be future proof and independent of the platforms you can read and write files in binaries. For example if this is Python on Windows, there could be some alternations done to the end of line. Hence reading and writing in Binary mode should help, using switches "rb" and "wb"
file = open("coordinates.kml", "wb")
And also remember to close the file session, else can throw errors while re running the script.
I'm trying to use a subprocess to write the output to a data file, and then parse through it in order to check for some data in it. However, when I need to do the reading through the file's lines, I always get a blank file unless I close the file and then reopen it. While it works, I just don't like having to do this and I want to know why it happens. Is it an issue with subprocess, or another intricacy of the file mode?
dumpFile=open(filename,"w+")
dump = subprocess.Popen(dumpPars,stdout=dumpFile)
dump.wait()
At this point, if I try to read the file, I get nothing. However, it works fine by doing these commands after:
dumpFile.close()
dumpFile=open(filename,"r")
The with statement automatically closes the file after the block ends:
with open(filename, "w+") as dumpFile:
dump = subprocess.Popen(dumpPars, stdout=dumpFile)
dump.wait()
with open(filename, "r") as dumpFile:
# dumpFile reading code goes here
You probably need to seek back to the beginning of the file, otherwise the file pointer will be at the end of the file when you try to read it:
dumpFile.seek(0)
However, if you don't need to actually store dumpFile, it's probably better to do something like:
dump = = subprocess.Popen(dumpPars,stdout=subprocess.PIPE)
stdoutdata,_ = dump.communicate() #now parse stdoutdata
unless your command produces large volumes of data.
If you want to read what you've already written, either close and reopen the file, or "rewind" it - seek to offset 0.
If you want to read the file while it is being written, you can do so (don't even need to write it to disk), see this other question Capture output from a program