trying to make a file that opens an existing text file and looks for a line number in that file. If the line number is not there I want it to print out a message that says that it is not in there.
This is what i have so far. And i am getting the Unexpected EOF error message. Where am I missing the problem?
# Get Input from user
file_name = input("Name of file to open please: ")
try:
in_file=open(file_name)
while True:
find_line = input("Which line number are you looking for? ")
try:
line_num=int(find_line)
line_count=1
for line_num in in_file:
if line_count== find_line:
print("Line number {} of the file {}, reads: {}".format(find_line,file_name,line_num))
break
line_count+=1
else:
print("Line number {} in file {} seems to be missing".format(find_line,file_name))
in_file.close()
in_file.open(file_name)
continue
break
except ValueError:
print("The Line Number you entered",find_line,"is not a correct line number")
in_file.close()
except IOError:
print ("Not sure how to break this to you, but the file your requested",file_str,"well, it's just not there")
print ("end of program")
That is to be expected. Your first try block doesn't have an except block.
try:
# Your code goes here
except:
print("Error")
Related
how can i find if a set of lines are present in a file and if present print "found" else "not found" using python.
Also if the line is not found i need the process to terminate and should not search for next line.
suppose the file contain data:
hi welcome to python
this is nice
this is bad
this is good
this is not correct
this is bad
this is bad for health
this is good for health
Here if this is good not present then i need the process to stop there and should not go to search for this is bad.
This is my current attempt
with open("model.log" , "r") as f:
lines = f.read().split('\n')
for line in lines:
if "this is good" in line:
print('Found the line and going to next level')
else:
print('not found')
if "this is bad" in line:
print('Found this line')
else:
print('stuck at the previous line')
if "good for health" in line:
print('Found it is there')
else:
print('error')
with open("model.log" , "r") as f:
lines = f.read().split('\n')
for line in list(enumerate(lines, start=1)):
if "this is good" == line[1]:
print(f'Found in line {line[0]}')
The break statement can be used to terminate a loop prematurely.
This might help.
E.g.:
for line in lines:
if "this is good" in line:
print('Found the line and going to next level')
else:
print('not found')
break #This will break the loop & execution will jumpt next line after loop
lines_to_search = ["this is good","this is bad","good for health"]
with open("model.log" , "r") as f:
file_lines = f.readlines()
for line in lines_to_serch:
if line in file_lines:
print(f"Found \"{line}\"")
else:
print(f"Not Found \"{line}\"")
break
You can try without for loop:
with open("model.log") as f:
lines = f.read().splitlines()
if "this is good" in lines:
print('Found the line and going to next level')
else:
print('not found')
if "this is bad" in lines:
print('Found this line')
else:
print('stuck at the previous line')
if "good for health" in lines:
print('Found it is there')
else:
print('error')
I'm trying to incorporate enumerate so I can give the user of the program where the line error was and the input of that line.
Here is my code:
elif response == 'data2':
print('Processing file:', response + '.txt')
try:
infile = open('data2.txt', 'r')
for line in infile:
amount = float(line)
total += amount
infile.close()
print(format(total, ',.2f'))
except IOError:
print("IO Error occurred trying to read the file.")
except ValueError:
print("Non-numeric data found in file:", response + '.txt')
except:
print("An error occurred.")
As you see I want the ValueErrorto output something along the lines of:
Non-numeric data found in file: data2.txt at line: 3 with input: three
hundred
I'm however stuck on how to accomplish this.
You can use the enumerate built-in function to get the line number:
elif response == 'data2':
print('Processing file:', response + '.txt')
try:
# Python allows you to iterate over a file object directly.
for line_no, line in enumerate(open('data2.txt', 'r')):
amount = float(line)
total += amount
print(format(total, ',.2f'))
except IOError:
print("IO Error occurred trying to read the file.")
except ValueError:
# I took the liberaty of formatting your output in a way
# that's a bit more readble than one long line of text.
print("Non-numeric data found in file: {}.txt at line: {}"
"with input: {}".format(response, line_no + 1, line))
except:
print("An error occurred.")
You need to track what line you are up to in the file, and catch the exception while reading.
for line_number, line in enumerate(infile, 1):
try:
amount = float(line)
except ValueError:
print(
"Non-numeric data found in file",
response + ".txt on line",
line_number,
"with input",
line
)
exit(1) # or whatever is appropriate for this script.
I have to write a program that will read data from a file, convert it to an integer and total the amount. So far here is what i have. The numbers from the data file "numdata.txt" are: 78,93,85,100,81,76,94,77.
def main():
total = 0
try:
NumberFile = open('numdata.txt', 'r')
for line in NumberFile:
amount = float(line)
total += amount
print(format(total, ',.2f'))
except IOError:
print('An error occurred trying to read the file.')
except ValueError:
print('Non-numeric data found in the file.')
except:
print('An error has occurred.')
finally:
NumberFile.close()
main()
When i run the program the first number (78) gets displayed and then one of the exception error messages comes up, the weird thing is that it's different sometimes. If someone could help point me in the right direction I'd appreciate it. I'm still very new to this so please bear with me.
I tried and tried but could not get the loop to work correctly so i ended up going this route:
def main ():
infile = open('numdata.txt', 'r')
num1 = int(infile.readline())
num2 = int(infile.readline())
num3 = int(infile.readline())
num4 = int(infile.readline())
num5 = int(infile.readline())
num6 = int(infile.readline())
num7 = int(infile.readline())
num8 = int(infile.readline())
infile.close()
total = num1+num2+num3+num4+num5+num6+num7+num8
average = total/8
print('the total: ', total)
print('the average: ', average)
main()
It's not pretty but it works i guess lol
total = 0
try:
NumberFile = open('numdata.txt', 'r')
for line in NumberFile:
amount = float(line)
total += amount
print(format(total, ',.2f'))
except IOError:
print('An error occurred trying to read the file.')
except ValueError:
print('Non-numeric data found in the file.')
except:
print('An error has occurred.')
finally:
NumberFile.close()
The exception occurs because you're closing the file immediately after the first iteration, leaving you unable to iterate over the rest of it.
Moving NumberFile.close() to a finally clause ensures the file is closed no matter what goes wrong. However, a much better way to read / write files in Python is to use the with keyword, which is a built-in method of ensuring the same thing.
total = 0
with open('numdata.txt', 'r') as f:
for line in f:
try:
total += float(line)
except ValueError:
print('Non-numeric data found in the file.')
continue
finally:
print('{:.2f}'.format(total, ',.2f'))
you are closing the file in first iteration NumberFile.close() is not indented properly
I am creating a program which asks the user to choose a file to run within the program but I can't stop the program from crashing when a file name that does not exist is entered. I have tried try statements and for loops but they have all given an error. The code I have for choosing the file is below:
data = []
print "Welcome to the program!"
chosen = raw_input("Please choose a file name to use with the program:")
for line in open(chosen):
our_data = line.split(",")
data.append(our_data)
Add an exception:
data = []
print "Welcome to the program!"
chosen = raw_input("Please choose a file name to use with the program:")
try:
for line in open(chosen):
our_data = line.split(",")
data.append(our_data)
except IOError:
print('File does not exist!')
Without using an exception you can simply check if the file exists and if not ask for it again.
import os.path
data = []
print "Welcome to the program!"
chosen='not-a-file'
while not os.path.isfile(chosen):
if chosen != 'not-a-file':
print("File does not exist!")
chosen = raw_input("Please choose a file name to use with the program:")
for line in open(chosen):
our_data = line.split(",")
data.append(our_data)
RTM
import sys
try:
f = open('myfile.txt')
s = f.readline()
i = int(s.strip())
except IOError as e:
print "I/O error({0}): {1}".format(e.errno, e.strerror)
except ValueError:
print "Could not convert data to an integer."
except:
print "Unexpected error:", sys.exc_info()[0]
raise
I am stuck why the words.txt is not showing the full grid, below is the tasks i must carry out:
write code to prompt the user for a filename, and attempt to open the file whose name is supplied. If the file cannot be opened the user should be asked to supply another filename; this should continue until a file has been successfully opened.
The file will contain on each line a row from the words grid. Write code to read, in turn, each line of the file, remove the newline character and append the resulting string to a list of strings.After the input is complete the grid should be displayed on the screen.
Below is the code i have carried out so far, any help would be appreciated:
file = input("Enter a filename: ")
try:
a = open(file)
with open(file) as a:
x = [line.strip() for line in a]
print (a)
except IOError as e:
print ("File Does Not Exist")
Note: Always avoid using variable names like file, list as they are built in python types
while True:
filename = raw_input(' filename: ')
try:
lines = [line.strip() for line in open(filename)]
print lines
break
except IOError as e:
print 'No file found'
continue
The below implementation should work:
# loop
while(True):
# don't use name 'file', it's a data type
the_file = raw_input("Enter a filename: ")
try:
with open(the_file) as a:
x = [line.strip() for line in a]
# I think you meant to print x, not a
print(x)
break
except IOError as e:
print("File Does Not Exist")
You need a while loop?
while True:
file = input("Enter a filename: ")
try:
a = open(file)
with open(file) as a:
x = [line.strip() for line in a]
print (a)
break
except IOError:
pass
This will keep asking untill a valid file is provided.