I have a question about the python read files(its format as txt ). I read a file and argv[1] is once read bytes number, and then put it sotre in a list, but when I write it on another file, it is not the same as the original files. how could i fix this?
readfile:
fh = open(file_name, "rb")
imfor = fh.read(mss)
file_content = []
file_content.append(imfor)
while (imfor):
file_content.append(imfor)
imfor = fh.read(mss)
fh.close()
write File
fh = open("test1R.txt", "wb")
for currContent in file_content:
fh.write(currContent)
fh.close
It is always better to use a the with open context manager to read and write files. You also don't need to manually append the contents to a list. file.readlines() does that for you.
Here is a some code to help you with that:
from sys import argv
# we first check if the file exists
try:
print("reading file")
with open(argv[1], "r") as input_file:
file_contents = input_file.readlines() # stores the file content in an array
except FileNotFoundError:
print(f"File {argv[1]} not found")
exit(1)
# check if the user provided a name for the output file
try:
out_file = argv[2]
except IndexError:
out_file = "outfile.txt"
# write to the new file.
with open(out_file, "w") as out:
try:
out.write("\n".join(file_contents)) # converts the array back to string
print(f"Wrote to {out_file}")
except FileExistsError:
print(f"{out_file} already exists.")
exit(1)
Related
So how can I ask the user to provide me with an input file and an output file?
I want the content inside the input file provided by the user to print into the output file the user provided. In this case, the user would put in this
Enter the input file name: copyFrom.txt
Enter the output file name: copyTo.txt
inside the input file is just the text "hello world".
Thanks. Please keep it as simple as you can if possible
If you just want to copy the file, shutil’s copy file does the loop implicitly:
import os
from shutil import copyfile
openfile = input('Enter the input file name:')
outputfile = input('Enter the output file name:')
copyfile(openfile, outputfile)
This this post How do I copy a file in Python? for more detail
Here is an example that should work in Python3. The input and output file names would need to include the full path (i.e. "/foo/bar/file.txt"
import os
input_file = input('Enter the input file name: ')
output_file = input('Enter the output file name: ')
def update_file(input_file, output_file):
try:
if os.path.exists(input_file):
input_fh = open(input_file, 'r')
contents = input_fh.readlines()
input_fh.close()
line_length = len(contents)
delim = ''
if line_length >= 1:
formatted_contents = delim.join(contents)
output_fh = open(output_file, 'w')
output_fh.write(formatted_contents)
output_fh.close()
print('Update operation completed successfully')
except IOError:
print(f'error occurred trying to read the file {input_fh}')
update_file(input_file, output_file)
You can do this...
import os
openfile = input('Enter the input file name:')
outputfile = input('Enter the output file name:')
if os.path.isfile(openfile):
file = open(openfile,'r')
output = open(outputfile,'w+')
output.write(file.read())
print('File written')
exit()
print('Origin file does not exists.')
To input the input-file and output-file names, simply use the input(s) function where s is the input message.
To get the "content inside the input file provided by the user to print into the output file," that would mean reading the input file and writing the read data into the output file.
To read the input file, use f = open(input_filename, 'r'), where the first argument is the filename and the second argument is the open mode where 'r' means read. Then letting readtext be the read text information of the input file, use readtext = f.read(): this returns the entire text content of f.
To output the read content to the output file, use g = open(output_filename, 'w'), noting that now the second argument is 'w', meaning write. To write the data, use g.write(readtext).
Please note that an exception will be raised if the input file is not found or the output file is invalid or not possible as of now. To handle these exceptions, use a try-except block.
This is effectively a file-copying operation in Python. shutil can serve as a useful alternative.
First you have to read the file and save it to some variable (here rd_data):
if os.path.exists(input_file_name):
f = open(input_file_name,"r")
rd_data = f.read()
f.close()
Then you have to write the variable to other file:
f = open(output_file_name,"w")
f.write(rd_data)
f.close()
The full code is given below:
import os
input_file_name = input("Enter file name to read: ")
output_file_name = input("Enter file name to write: ")
if os.path.exists(input_file_name):
f = open(input_file_name,"r")
rd_data = f.read()
f.close()
f = open(output_file_name,"w")
f.write(rd_data)
f.close()
I have many text files, and each of them has a empty line at the end. My scripts did not seem to remove them. Can anyone help please?
# python 2.7
import os
import sys
import re
filedir = 'F:/WF/'
dir = os.listdir(filedir)
for filename in dir:
if 'ABC' in filename:
filepath = os.path.join(filedir,filename)
all_file = open(filepath,'r')
lines = all_file.readlines()
output = 'F:/WF/new/' + filename
# Read in each row and parse out components
for line in lines:
# Weed out blank lines
line = filter(lambda x: not x.isspace(), lines)
# Write to the new directory
f = open(output,'w')
f.writelines(line)
f.close()
You can use Python's rstrip() function to do this as follows:
filename = "test.txt"
with open(filename) as f_input:
data = f_input.read().rstrip('\n')
with open(filename, 'w') as f_output:
f_output.write(data)
This will remove all empty lines from the end of the file. It will not change the file if there are no empty lines.
you can remove last empty line by using:
with open(filepath, 'r') as f:
data = f.read()
with open(output, 'w') as w:
w.write(data[:-1])
You can try this without using the re module:
filedir = 'F:/WF/'
dir = os.listdir(filedir)
for filename in dir:
if 'ABC' in filename:
filepath = os.path.join(filedir,filename)
f = open(filepath).readlines()
new_file = open(filepath, 'w')
new_file.write('')
for i in f[:-1]:
new_file.write(i)
new_file.close()
For each filepath, the code opens the file, reads in its contents line by line, then writes over the file, and lastly writes the contents of f to the file, except for the last element in f, which is the empty line.
You can remove the last blank line by the following command. This worked for me:
file = open(file_path_src,'r')
lines = file.read()
with open(file_path_dst,'w') as f:
for indx, line in enumerate(lines):
f.write(line)
if indx != len(lines) - 1:
f.write('\n')
i think this should work fine
new_file.write(f[:-1])
I would like to loop through files into a directory, make something on these files and then for each file write out the result.
But my files can't be read because python interprets file names as string objects and not a readable file.
Is there a way to avoid this?
import re
import os
def create_filename_for_fileout (f1):
fileout_n = f1.replace("TT", "out")
fileout = "C:\\Users\\KP\\Desktop\\FSC_Treetag\\out\\"+str(fileout_n)
return fileout
for file_in in os.listdir('C:\\Users\\KP\\Desktop\\FSC_Treetag'):
filename = str(file_in)
file_out = create_filename_for_fileout(filename)
open(file_in, 'r')
open(file_out, 'w')
content_file = file_in.readlines()
for ln in content_file:
regex = re.compile('(.*\t(ADJ|ADV|NOM|VER:cond|VER:futu|VER:impe|VER:impf|VER:infi|VER:pper|VER:pres|VER:pres|VER:simp|VER:subi|VER:subp)\t(.*))')
res = regex.search(ln)
if res:
# categ = res.group(2)
lemme = res.group(3)
file_out.write(str(lemme)+"\n")
file_out.close()
file_in.close()
Result:
content_file = file_in.readlines()
AttributeError: 'str' object has no attribute 'readlines'
>>>
You're not assigning your open to any variable to use.
# Change
open(file_in, 'r')
open(file_out, 'w')
# to
input_file = open(file_in, 'r')
output_file = open(file_out, 'w')
for ln in input_file:
# do your processing
if res:
lemme = res.group(3)
output_file.write(str(lemme) + "\n")
You are not assigning the open functions to the respective handlers (open is returning an object of the file type).
filename = str(file_in)
file_out = create_filename_for_fileout(filename)
open(file_in, 'r')
open(file_out, 'w')
Should be:
file_out = open(create_filename_for_fileout(file_in), 'w')
file_in = open(file_in, 'r')
NOTE: for clarity sake it's a good idea to use another pointer for the infile handler.
Check: https://docs.python.org/2/library/functions.html#open
open(name[, mode[, buffering]])
Open a file, returning an object of the file type described in section File Objects. If the file cannot be opened, IOError is raised.
Thanks to stackoverflow, I am able to read and copy a file. However, I need to read a picture file one line at a time, and the buffer array can't exceed 3,000 integers. How would I separate the lines, read them, and then copy them? Is that the best way to execute this?
Here is my code, courtesy of #Chayim:
import os
import sys
import shutil
import readline
source = raw_input("Enter source file path: ")
dest = raw_input("Enter destination path: ")
file1 = open(source,'r')
if not os.path.isfile(source):
print "Source file %s does not exist." % source
sys.exit(3)
file_line = infile.readline()
try:
shutil.copy(source, dest)
infile = open(source,'r')
outfile = open(dest,'r')
file_contents = infile.read()
file_contents2 = outfile.read()
print(file_contents)
print(file_contents2)
infile.close()
outfile.close()
except IOError, e:
print "Could not copy file %s to destination %s" % (source, dest)
print e
sys.exit(3)
I added
file_line = infile.readline()
but I'm concerned that infile.readline() will return a string, instead of integers. Also, how do I limit the number of integers it processes?
I think you want to do something like this:
infile = open(source,'r')
file_contents_lines = infile.readlines()
for line in file_contents_lines:
print line
This will get you all the lines in the file and put them into a list containing each line as an element in the list.
Take a look at the documentation here.
Currently I'm using this:
f = open(filename, 'r+')
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.write(text)
f.close()
But the problem is that the old file is larger than the new file. So I end up with a new file that has a part of the old file on the end of it.
If you don't want to close and reopen the file, to avoid race conditions, you could truncate it:
f = open(filename, 'r+')
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.write(text)
f.truncate()
f.close()
The functionality will likely also be cleaner and safer using open as a context manager, which will close the file handler, even if an error occurs!
with open(filename, 'r+') as f:
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.write(text)
f.truncate()
The fileinput module has an inplace mode for writing changes to the file you are processing without using temporary files etc. The module nicely encapsulates the common operation of looping over the lines in a list of files, via an object which transparently keeps track of the file name, line number etc if you should want to inspect them inside the loop.
from fileinput import FileInput
for line in FileInput("file", inplace=1):
line = line.replace("foobar", "bar")
print(line)
Probably it would be easier and neater to close the file after text = re.sub('foobar', 'bar', text), re-open it for writing (thus clearing old contents), and write your updated text to it.
I find it easier to remember to just read it and then write it.
For example:
with open('file') as f:
data = f.read()
with open('file', 'w') as f:
f.write('hello')
To anyone who wants to read and overwrite by line, refer to this answer.
https://stackoverflow.com/a/71285415/11442980
filename = input("Enter filename: ")
with open(filename, 'r+') as file:
lines = file.readlines()
file.seek(0)
for line in lines:
value = int(line)
file.write(str(value + 1))
file.truncate()
Honestly you can take a look at this class that I built which does basic file operations. The write method overwrites and append keeps old data.
class IO:
def read(self, filename):
toRead = open(filename, "rb")
out = toRead.read()
toRead.close()
return out
def write(self, filename, data):
toWrite = open(filename, "wb")
out = toWrite.write(data)
toWrite.close()
def append(self, filename, data):
append = self.read(filename)
self.write(filename, append+data)
Try writing it in a new file..
f = open(filename, 'r+')
f2= open(filename2,'a+')
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.close()
f2.write(text)
fw.close()