Python error message io.UnsupportedOperation: not readable
Note: opening file in a block makes sure that the file is properly closed at the block’s end, even if an exception is raised on the way. Question: I made a simple program but It shows the following error when I run it: It shows this error message: Solution 1: You are opening the file as , which stands for writable.
Python error message io.UnsupportedOperation: not readable
I made a simple program but It shows the following error when I run it:
line1 = [] line1.append("xyz ") line1.append("abc") line1.append("mno") file = open("File.txt","w") for i in range(3): file.write(line1[i]) file.write("\n") for line in file: print(line) file.close() It shows this error message:
File «C:/Users/Sachin Patil/fourth,py.py», line 18, in
for line in file:UnsupportedOperation: not readable
You are opening the file as «w» , which stands for writable.
Using «w» you won’t be able to read the file. Use the following instead:
Additionally, here are the other options:
"r" Opens a file for reading only. "r+" Opens a file for both reading and writing. "rb" Opens a file for reading only in binary format. "rb+" Opens a file for both reading and writing in binary format. "w" Opens a file for writing only. "a" Open for writing. The file is created if it does not exist. "a+" Open for reading and writing. The file is created if it does not exist. Use a+ to open a file for reading, writing and create it if it doesn’t exist.
a+ Opens a file for both appending and reading. The file pointer is at the end of the file if the file exists. The file opens in the append mode. If the file does not exist, it creates a new file for reading and writing. -Python file modes
with open('"File.txt', 'a+') as file: print(file.readlines()) file.write("test") Note: opening file in a with block makes sure that the file is properly closed at the block’s end, even if an exception is raised on the way. It’s equivalent to try-finally , but much shorter.
If you want to read from file you should type file = open(«File.txt»,»r») , if write than file = open(«File.txt»,»w») . You need to give the right permission regarding your usage.
- r. Opens a file for reading only.
- rb. Opens a file for reading only in binary format.
- r+ Opens a file for both reading and writing.
- rb+ Opens a file for both reading and writing in binary format.
- w. Opens a file for writing only.
- you can find more modes in here
This will let you read, write and create the file if it don’t exist:
f = open('filename.txt','a+') f = open('filename.txt','r+') f.readline() #Read next line f.seek(0) #Jump to beginning f.read(0) #Read all file f.write('test text') #Write 'test text' to file f.close() #Close file Python — io.UnsupportedOperation: not readable, The first problem, as JBernardo pointed out, is that you’ve opened the file in «a» mode, which means «write-only, appending to the end». You can use «a+» or «r+» if you want to read and write. However, that won’t really help you. After all, you can’t write to the file in the middle of reading it.
Python Error io.UnsupportedOperation: not readable
i have this error and i don’t know why i got it. I followed the steps from my Python manual and i got this. I am tryng to cleanup the file on column 8 and 9 if they have that odd character. If someone could help me, please advise.
The error appear on the line of code: for row in csv.reader(f):
Please find below my code:
import csv file = '/Users/cohen/Desktop/sdn-2.csv' newstring = "null" newinteger = int(0) with open(file, 'r+') as f: for row in csv.reader(f): if row[7] =="-0-": row[7] = newinteger if row[8] == "-0-": row[8] = newinteger f.close() ***LATER EDIT I changed the code as above, but is not doing anything is not replacing the -0- with 0
You need to open the file with r+. Using w is for write only, r+ is for both write and read access.
Using == as in row[7] == newinteger is calling the equality operator. It checks if the left and right operand’s values are the same. You want to be setting the new value with = .
The other stuff that those before me said too but I think this error is from the parentheses around the string «-0-» . And maybe the space on the first use as well.
This was my solution: to create an output file and to write in it, what i read from the source file. Is a bit odd, as in VBA was even easier to do this, then in python, but this is the solution within the csv module from pythn. I dont like that i have to create another file, and i can’t basicaly write inside the readed file, and i have to write into a brand new file, but this is life. If someone has a better approach, I am opened to new.
Hope that others will use this code.
import csv newstring = "null" newinteger = (0) with open('/Users/cohen/Desktop/sdn-4 2.csv', 'r') as file1, open('/Users/cohen/Desktop/new_sdn.csv', 'w', newline='') as file2: reader = csv.reader(file1, delimiter=',') writer = csv.writer(file2, delimiter=',') for row in reader: replaced1 = row[7].replace('-0-', newstring) row[7]=replaced1 replaced2 = row[8].replace('-0-', newinteger) row[8]=replaced2 writer.writerow(row) Why can’t handle «io.UnsupportedOperation» error by try, Running the following code will raise an io.UnsupportedOperation error, because the file is open in «write» mode — with open(«hi.txt», «w») as f: print(f.read()) The output is — io.UnsupportedOperation: not readable So, we can try to cover this up by doing this —
Io.UnsupportedOperation: not readable
I am working on a problem that says to make a program that gets a user input for a file and then within the file removes a string that the user specifies. I’m not sure how to go from what I have(below) to what the question asks for. As always any and all help is greatly appreciated.
def main(): outfile = open(input("Enter a file name: "), "a") string = input("Enter the string to be removed: ") for string in outfile.readlines(): string = string.replace(string, "") outfile.close() print("Done") main() I took one of the suggestions and tried to get it to work but as I said in my comment below the code below does not return an error it creates an empty file. What am I missing to get the new file to be the old file with the string removed?
def main(): inpath = input("Enter an input file: ") line = input("Enter what you want to remove: ") outpath = input("Enter an output file: ") with open(inpath, "r") as infile, open(outpath, "w") as outfile: for line in infile: outfile.write(line.replace(line, "") + "\n") print("Done.") main() A few side notes before getting into the details: When you call string.replace(string, «») , you’re telling the string to replace its entire self with the empty string—you might as well just do string = «» . Presumably the first string is the search string to replace, so give it a different name, and then use it as, e.g., string.replace(searchString, «») . Also, you don’t want to name a variable string , because it’s the name of a standard library module. You’re calling your input file «outfile», which is apt to be confusing. You probably want to use a with statement instead of an explicit close. Finally, you can iterate the lines in a file with just for line in f: ; you don’t need for line in f.readlines() (and, if you ever need to deal with Python 2.x, you’ll be much happier avoiding readlines() , because it will read the entire file into memory, and then make a huge list of lines in memory).
The first problem, as JBernardo pointed out, is that you’ve opened the file in «a» mode, which means «write-only, appending to the end». You can use «a+» or «r+» if you want to read and write.
However, that won’t really help you. After all, you can’t write to the file in the middle of reading it.
There are a few common ways around this.
First, just write to standard output, and let the user do whatever he wants with the results—e.g., redirect it to a file. (In that case, you have print your prompt, «Done» message, etc. to standard error instead, so they don’t get redirected to the file.) This is what many Unix tools like sed or sort do, so it’s appropriate if you’re building a Unix-style tool, but may not be right for other purposes.
def stderrinput(prompt): sys.stderr.write(prompt) sys.stderr.flush() return input() def main(): with open(stderrinput("Enter a file name: "), "r") as infile: searchString = stderrinput("Enter the string to be removed: ") for line in infile: print(infile.replace(searchString, "")) sys.stderr.write("Done\n") Second, write to another file. Open the input file in «r» mode, and the output file in «w», mode, and then you’re just copying lines:
def main(): inpath = input("Enter an input file: ") outpath = input("Enter an output file: ") with open(inpath, "r") as infile, open("outpath", "w") as outfile: for line in infile: outfile.write(line.replace(searchString, "") + "\n") Third, read and process the whole file in memory, then truncate and rewrite the whole file:
def main(): path = input("Enter an input/output file: ") with open(path, "r+") as inoutfile: lines = [line.replace(searchString, "") for line in inoutfile] inoutfile.seek(0) inoutfile.truncate() inoutfile.writelines(lines) Finally, write to a temporary file (as with the second option), then move that temporary file on top of the original input file. Something like this:
def main(): path = input("Enter an input/output file: ") with open(path, "r") as infile, tempfile.NamedTemporaryFile("w", delete=False) as outfile: for line in infile: outfile.write(line.replace(searchString, "")) shutil.move(outfile.name, pathname) This last one is a little tricky, because of the differences between POSIX and Windows. However, it has some big advantages. (For example, if your program gets killed in the middle of operation, no matter how it happens, you’re guaranteed to have either the original file or the new file, not some half-written mess.)
Getting an error in Python when trying to use stdin: io, I read the xml file from subversion, updated a line in the file and now I am trying to create a jenkins job by using subporcess.Popen and stdin test = subprocess. Stack Overflow. About; Products For Teams; Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & …