I want to append a previously-written binary file with a more recent binary file created.
Essentially merging them. This is the sample code I am using:
with open("binary_file_1", "ab") as myfile:
myfile.write("binary_file_2")
Except the error I get is "TypeError: must be string or buffer, not file"
But that's exactly what I am wanting to do! Add one binary file to the end of an earlier created binary file.
I did try adding "wb" to the "myfile.write("binary_file_2", "wb")but it didn't like that.
You need to actually open the second file and read its contents:
with open("binary_file_1", "ab") as myfile, open("binary_file_2", "rb") as file2:
myfile.write(file2.read())
From the python module shutil
import os
import shutil
WDIR=os.getcwd()
fext=open("outputFile.bin","wb")
for f in lstFiles:
fo=open(os.path.join(WDIR,f),"rb")
shutil.copyfileobj(fo, fext)
fo.close()
fext.close()
First we open the the outputFile.bin binary file for writing and then I loop over the list of files in lstFiles using the shutil.copyfileobj(src,dest) where src and dest are file objects. To get the file object just open the file by calling open on the filename with the proper mode "rb" read binary. For each file object opened we must close it. The concatenated file must be closed as well.
I hope it helps
for file in files:
async with aiofiles.open(file, mode='rb') as f:
contents = await f.read()
if file == files[0]:
write_mode = 'wb' # overwrite file
else:
write_mode = 'ab' # append to end of file
async with aiofiles.open(output_file), write_mode) as f:
await f.write(contents)
Related
I have a python function here that takes in 2 params, old_file is the name of the file that contains the content that I want to copy over to the new file and the new_file is the name for the file I want to create. Right now my code looks like this and it would throw an error which is a type error that says "TypeError: expected str, bytes or os.PathLike object, not TextIOWrapper". Is there a more efficient way to do it?. In addition when I point at with open(file, "r+") as f2: I get this warning
Note. this works if the file is already pre-made but not when i make it in the function
def copy_In(old_file, new_file):
file = open(new_file, "w")
with open(file, "r+") as f2:
for x in range(10):
f2.readline()
pos = f2.tell()
f2_remainder = f2.read()
f2.seek(pos)
with open(old_file, "r") as f1:
for line in f1:
f2.write(line)
f2.write(f2_remainder)
just do it like:
def copy_file(old_fname, new_fname):
with open(old_fname, "rt") as old_fobj, open(new_fname, "wt") as new_fobj:
new_fobj.write(old_fobj.read())
we are opening first file in read mode and second in write mode and reading the entire content of first file and writing it in second file.
I need to append many binary files in one binary file. All my binary files are saved i one folder:
file1.bin
file2.bin
...
For that I try by using this code:
import numpy as np
import glob
import os
Power_Result_File_Path ="/home/Deep_Learning_Based_Attack/Test.bin"
Folder_path =r'/home/Deep_Learning_Based_Attack/Test_Folder/'
os.chdir(Folder_path)
npfiles= glob.glob("*.bin")
loadedFiles = [np.load(bf) for bf in binfiles]
PowerArray=np.concatenate(loadedFiles, axis=0)
np.save(Power_Result_File_Path, PowerArray)
It gives me this error:
"Failed to interpret file %s as a pickle" % repr(file))
OSError: Failed to interpret file 'file.bin' as a pickle
My problem is how to concatenate binary file it is not about anaylysing every file indenpendently.
Taking your question literally: Brute raw data concatenation
files = ['my_file1', 'my_file2']
out_data = b''
for fn in files:
with open(fn, 'rb') as fp:
out_data += fp.read()
with open('the_concatenation_of_all', 'wb') as fp:
fp.write(out_data)
Comment about your example
You seem to be interpreting the files as saved numpy arrays (i.e. saved via np.save()). The error, however, tells me that you didn't save those files via numpy (because it fails decoding them). Numpy uses pickle to save and load, so if you try to open a random non-pickle file with np.load the call will throw an error.
for file in files:
async with aiofiles.open(file, mode='rb') as f:
contents = await f.read()
if file == files[0]:
write_mode = 'wb' # overwrite file
else:
write_mode = 'ab' # append to end of file
async with aiofiles.open(output_file), write_mode) as f:
await f.write(contents)
I'm trying to learn to manipulate files on python, but I can't get the open function to work. I have made a .txt file called foo that holds the content "hello world!" in my user directory (/home/yonatan) and typed this line into the shell:
open('/home/yonatan/foo.txt')
What i get in return is:
<_io.TextIOWrapper name='/home/yonatan/foo.txt' mode='r' encoding='UTF-8'>
I get what that means, but why don't I get the content?
open() returns a file object.
You then need to use read() to read the whole file
f = open('/home/yonatan/foo.txt', 'r')
contents = f.read()
Or you can use readline() to read just one line
line = f.readline()
and don't forget to close the file at the end
f.close()
An example iterating through the lines of the file (using with which ensures file.close() gets called on the end of it's lexical scope):
file_path = '/home/yonatan/foo.txt'
with open(file_path) as file:
for line in file:
print line
A great resource on I/O and file handling operations.
You haven't specified the mode you want to open it in.
Try:
f = open("home/yonatan/foo.txt", "r")
print(f.read())
Goal = Open file, encrypt file, write encrypted file.
Trying to use the PyPDF2 module to accomplish this. I have verified theat "input" is a file type object. I have researched this error and it translates to "file not found". I believe that it is linked somehow to the file/file path but am unsure how to debug or troubleshoot. and getting the following error:
Traceback (most recent call last):
File "CommissionSecurity.py", line 52, in <module>
inputStream = PyPDF2.PdfFileReader(input)
File "build\bdist.win-amd64\egg\PyPDF2\pdf.py", line 1065, in __init__
File "build\bdist.win-amd64\egg\PyPDF2\pdf.py", line 1660, in read
IOError: [Errno 22] Invalid argument
Below is the relevant code. I'm not sure how to correct this issue because I'm not really sure what the issue is. Any guidance is appreciated.
for ID in FileDict:
if ID in EmailDict :
path = "C:\\Apps\\CorVu\\DATA\\Reports\\AlliD\\Monthly Commission Reports\\Output\\pdcom1\\"
#print os.listdir(path)
file = os.path.join(path + FileDict[ID])
with open(file, 'rb') as input:
print type(input)
inputStream = PyPDF2.PdfFileReader(input)
output = PyPDF2.PdfFileWriter()
output = inputStream.encrypt(EmailDict[ID][1])
with open(file, 'wb') as outputStream:
output.write(outputStream)
else : continue
I think your problem might be caused by the fact that you use the same filename to both open and write to the file, opening it twice:
with open(file, 'rb') as input :
with open(file, 'wb') as outputStream :
The w mode will truncate the file, thus the second line truncates the input.
I'm not sure what you're intention is, because you can't really try to read from the (beginning) of the file, and at the same time overwrite it. Even if you try to write to the end of the file, you'll have to position the file pointer somewhere.
So create an extra output file that has a different name; you can always rename that output file to your input file after both files are closed, thus overwriting your input file.
Or you could first read the complete file into memory, then write to it:
with open(file, 'rb') as input:
inputStream = PyPDF2.PdfFileReader(input)
output = PyPDF2.PdfFileWriter()
output = input.encrypt(EmailDict[ID][1])
with open(file, 'wb') as outputStream:
output.write(outputStream)
Notes:
you assign inputStream, but never use it
you assign PdfFileWriter() to output, and then assign something else to output in the next line. Hence, you never used the result from the first output = line.
Please check carefully what you're doing, because it feels there are numerous other problems with your code.
Alternatively, here are some other tips that may help:
The documentation suggests that you can also use the filename as first argument to PdfFileReader:
stream – A File object or an object that supports the standard read
and seek methods similar to a File object. Could also be a string
representing a path to a PDF file.
So try:
inputStream = PyPDF2.PdfFileReader(file)
You can also try to set the strict argument to False:
strict (bool) – Determines whether user should be warned of all
problems and also causes some correctable problems to be fatal.
Defaults to True.
For example:
inputStream = PyPDF2.PdfFileReader(file, strict=False)
Using open(file, 'rb') was causing the issue becuase PdfFileReader() does that automagically. I just removed the with statement and that corrected the problem.
with open(file, 'rb') as input:
inputStream = PyPDF2.PdfFileReader(input)
This error raised up because of PDF file is empty.
My PDF file was empty that's why my error was raised up. So First of all i fill my PDF file with some data and Then start reeading it using PyPDF2.PdfFileReader,
And it solved my Problem!!!
Late but, you may be opening an invalid PDF file or an empty file that's named x.pdf and you think it's a PDF file
im trying to create a script that opens a file and replace every 'hola' with 'hello'.
f=open("kk.txt","w")
for line in f:
if "hola" in line:
line=line.replace('hola','hello')
f.close()
But im getting this error:
Traceback (most recent call last):
File "prueba.py", line 3, in
for line in f: IOError: [Errno 9] Bad file descriptor
Any idea?
Javi
open('test.txt', 'w').write(open('test.txt', 'r').read().replace('hola', 'hello'))
Or if you want to properly close the file:
with open('test.txt', 'r') as src:
src_text = src.read()
with open('test.txt', 'w') as dst:
dst.write(src_text.replace('hola', 'hello'))
Your main issue is that you're opening the file for writing first. When you open a file for writing, the contents of the file are deleted, which makes it quite difficult to do replacements! If you want to replace words in the file, you have a three-step process:
Read the file into a string
Make replacements in that string
Write that string to the file
In code:
# open for reading first since we need to get the text out
f = open('kk.txt','r')
# step 1
data = f.read()
# step 2
data = data.replace("hola", "hello")
f.close()
# *now* open for writing
f = open('kk.txt', 'w')
# step 3
f.write(data)
f.close()
You've opened the file for writing, but you're reading from it. Open the original file for reading and a new file for writing. After the replacement, rename the original out and the new one in.
You could also have a look at the with statement.