I tried the below code with pycharm IDE and found that file is being created for append mode.
As we learn in course lecture that file will be created only with write mode ='w'
with open('xyz.txt',mode= 'a') as xyz_file:
xyz_file.write('This file is created in append mode')
with open('xyz.txt',mode= 'r') as xyz_file:
print(xyz_file.read())
I was aware that there is no file that exists with the name xyz.txt in my python file path. yet with the above code, it is created and the text appended.
The python open() command will create the file if the mode is 'w', 'a', or 'x'.
I believe that if you want to be able to write in a file but still error if the file is not created, the 'r+' mode will do that.
Related
I am new to image processing and what I am trying to do is resize an image and store it in tif format, but command window reports an error saying "you don't have the permission to write"
my code is imwrite(B,'myNewFile.tif');
and after running it shows
Error using imwrite (line 10)
Unable to open file "myNewFile.tif" for writing. You may not have write permission.
Do I have to create a file by the name 'myNewFile' before writing the above code?
As the error message states, you are trying to write the file myNewFile.tif to the current working directory. However, you do not have writing permission in the current working direcoty. This is an OS issue, not a Matlab one.
What you can do is change the current working directory (using cd command) and write the image to a different folder where you do have writing permissions.
Alternatively, you can supply a full path to the image file name, directing it to a folder where you have writing permissions.
imwrite( B, fullfile( '/path/to/where/you/can/write', 'myNewFile.tif' ) );
Here are links to the description of some Matlab commands that might help you:
pwd can be used to check what is your current working directory.
You can use cd to change the current working directory.
fullfile helps you construct file names and paths in a generic way without worrying about OS pecularities.
I am trying to generate a bulkloader.yaml file in this way
appcfg.py create_bulkloader_config --filename=bulkloader.yaml --url=http://your_app_id.appspot.com/_ah/remote_api
but I get this error
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/bulkloader.py", line 3839, in CheckOutputFile
raise FileExistsError('%s: output file exists' % filename)
I can't manage to find where such file is
consider I am using Eclipse PyDev on Mac Os through the GoogleAppEngineLauncher
Couple of things:
1) you are missing the --application=s~your_app_id tag
2) What directory are you in when you run this? If you are not sure run cd path/to/where/you/want/it
3) You can always try to find it using Mac's Spotlight, in case you are not sure where it saved.
all. I had some questions about the Perl module HTTP::Cookies. The example on CPAN is like below:
$cookie_jar = HTTP::Cookies->new( file => '$ENV{\'HOME\'}/lwp_cookies.dat', autosave => 1);
The lwp_cookies.dat file is used to save cookie data on my local machine as I understand. On my machine, '$ENV{\'HOME\'}' is an empty path. The script runs good, even after execution I can't find any file named "lwp_cookies.dat" on my machine. I changed '$ENV{\'HOME\'}' to '$ENV{\'TMP\'}', which is a path really exists after I verified by Perl print. Still I can't find the "lwp_cookies.dat" in my TEMP folder. My first question is how the HTTP::Cookies is working with the "lwp_cookies.dat" file.
On the other hand, on one of my systems(all're Windows system as mentioned here), the same code produce error message below:
Can't open $ENV{'HOME'}/lwp_cookies.dat: No such file or directory
So it's strange to me. On my good system, even file or path not exists, the script runs well, which I suppose the file is created on some temp memory instead; on bad system, the code example doesn't work at all.
If you want the $ENV{'HOME'} variable to interpolate into the string, you need double quotes; single quotes don't interpolate variables:
`file => "$ENV{'HOME'}/lwp_cookies.dat",`
Hallo everyone once again,
I did various searches but couldn't gind a suitable/applicable answer to the simple problem below:
On pgAdminIII (Windows 7 64-bit) I am running the following command using SQL editor:
COPY public.Raw20120113 FROM 'D:\my\path\to\Raw CSV Data\13_01_2012.csv';
I tried many different variations for the path name and verified the path, but I keep getting:
ERROR: could not open file "D:\my\path\to\Raw CSV Data\13_01_2012.csv" for reading: No such file or directory
Any suggestions why this happens?
Thank you all in advance
Petros
UPDATE!!
After some tests I came to the following conclusion: The reason I am getting this error is that the path includes some Greek characters. So, while Windows uses codepage 1253, the console is using 727 and this whole thing is causing the confusion. So, some questions arise, you may answer them if you like or prompt me to other questions?
1) How can I permanently change the codepageof the console?
2) How can I define the codepage is SQL editor?
Thank you again, and sorry if the place to post the question was inappropriate!
Try DIR "D:\my\path\to\Raw CSV Data\13_01_2012.csv" from command line and see if it works - just to ensure that you got the directory, file name, extension etc correct.
The problem is that COPY command runs on server so it takes the path to the file from the server's scope.
To use local file to import you need to use \COPY command. This takes local path to the file into account and loads it correctly.
Setup:
Windows 7 Enterprise.
Matlab 7.10.0 (R2010a).
mcc compiler: Microsoft Visual C++ 2008 Express.
What's happening:
My project runs fine when running it through Matlab, but when trying to run the .exe through the command prompt after using mcc to compile, the command prompt generates an error.
The mcc command I issue is:
mcc -m -v STARTUP1.m -o EXE_REDUC
The error I receive in the command prompt is:
??? Error using ==> textscan
Invalid file identifier. Use fopen to generate a valid file identifier.
I have a file called LoadXLS.m that loads and reads a .csv file using:
fid = fopen(file,'r');
temp_data = textscan(fid,...args...);
And then I process temp_data.
The csv file I'm trying to load is called spec.csv. It is located two directories down from where I have STARTUP1.m stored. The location of STARTUP1.m is also the place that the mcc generated files are stored to. I have used the pathtool to "Add with subfolders" this location, but am aware that those locations are not transferred to mbuild when compiling.
What I've Tried:
I have gone in and added print statements to print the value of fid to make sure it is valid. When I run it in Matlab, it has a valid value, however when I run in the command prompt it always returns an invalid value of -1.
I have removed all addpath() calls, I have tried adding the STARTUP1.m directory to the mcc ctf archive using:
mcc -m -v -a 'C:\Users\...path...\STARTUP1.m_location' STARTUP1.m -o EXE_REDUC;
However when I do this, I get a different error when running in the command prompt:
Cannot open CTF archive file
'C:\...path...\AppData\Local\Temp\mathworks_tmp_7532_28296'
or
'C:\...path...\AppData\Local\Temp\mathworks_tmp_7532_28296.zip'
??? Undefined function or variable 'matlabrc'.
To fix this, I've tried adding the pragma
%#function matlabrc
to the top of STARTUP1.m to try and enforce its inclusion, but had no success.
I also copied the spec.csv file to a new directory in the ctfroot and changed
fid = fopen(...)
to:
[tempFile, message] = fopen(fullfile(ctfroot, 'Added Config Files', ad.spec_file));
The message is:
message is: No such file or directory
Objective:
Rearranging file locations is a sufficient workaround while the exectuable only runs on my computer, however the idea is to take this standalone and distribute it to multiple people on many different computers. I would like to be able to have a top folder with a startup file and within this folder, have as many subfolders as the package requires. The startup file should be able to access all subfolders and files within them as necessary.
I read something about the exectuable actually running from a "secret location" on the machine here: http://matlab.wikia.com/wiki/FAQ
I would just like to be able to group one entire folder tree with all its files into a package containing the executable and be able to run it anywhere.
More info:
When I put the spec.csv file in the same directory as STARUTP1.m, it finds it fine using mcc without the -a 'path' option and using the following in the LoadXLS.m file:
[tempFile, message] = fopen(ad.spec_file,'r');
This project contains GUIs, generates PDFs, generates plots, and also creates a zip directory.
Thank you in advance.