Write output file, collating groups of up to 7 input lines
$begingroup$
I have this code that reads a file and after processing a few lines writes the output to a second file:
num_reads = 7
with open('data.txt') as read_file:
with open('new_data.txt', 'w') as write_file:
while (True):
lines =
try: # expect errors if the number of lines in the file are not a multiplication of num_reads
for i in range(num_reads):
lines.append(next(read_file)) # when the file finishes an exception occurs here
#do sutff with the lines (exactly num_reads number of lines)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
except StopIteration: # here we process the (possibly) insufficent last lines
#do stuff with the lines (less that num_reads)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
break
Here is the input file (data.txt):
line1
line2
line3
line4
line5
line7
line8
line9
And this is the output file that has the desired state:
line1 line2 line3 line4 line5 line7
line8 line9
This works correctly but as I wish to do the same processing and writing procedure in both cases (when the number of elements is 7 and when the file finishes and the exception is raised) I think the above code violates DRY principle even if I define a new function and call it once in try block and once in except before break. Any other ordering that I could come up with was either causing an infinite loop or losing the final lines.
I appreciate any comments on handling this issue, as it is not limited to this case and I had faced it in other cases as well.
python file
edited 10 mins ago
200_success
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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add a comment |
$begingroup$
I have this code that reads a file and after processing a few lines writes the output to a second file:
num_reads = 7
with open('data.txt') as read_file:
with open('new_data.txt', 'w') as write_file:
while (True):
lines =
try: # expect errors if the number of lines in the file are not a multiplication of num_reads
for i in range(num_reads):
lines.append(next(read_file)) # when the file finishes an exception occurs here
#do sutff with the lines (exactly num_reads number of lines)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
except StopIteration: # here we process the (possibly) insufficent last lines
#do stuff with the lines (less that num_reads)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
break
Here is the input file (data.txt):
line1
line2
line3
line4
line5
line7
line8
line9
And this is the output file that has the desired state:
line1 line2 line3 line4 line5 line7
line8 line9
This works correctly but as I wish to do the same processing and writing procedure in both cases (when the number of elements is 7 and when the file finishes and the exception is raised) I think the above code violates DRY principle even if I define a new function and call it once in try block and once in except before break. Any other ordering that I could come up with was either causing an infinite loop or losing the final lines.
I appreciate any comments on handling this issue, as it is not limited to this case and I had faced it in other cases as well.
python file
edited 10 mins ago
200_success
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago
add a comment |
$begingroup$
I have this code that reads a file and after processing a few lines writes the output to a second file:
num_reads = 7
with open('data.txt') as read_file:
with open('new_data.txt', 'w') as write_file:
while (True):
lines =
try: # expect errors if the number of lines in the file are not a multiplication of num_reads
for i in range(num_reads):
lines.append(next(read_file)) # when the file finishes an exception occurs here
#do sutff with the lines (exactly num_reads number of lines)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
except StopIteration: # here we process the (possibly) insufficent last lines
#do stuff with the lines (less that num_reads)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
break
Here is the input file (data.txt):
line1
line2
line3
line4
line5
line7
line8
line9
And this is the output file that has the desired state:
line1 line2 line3 line4 line5 line7
line8 line9
This works correctly but as I wish to do the same processing and writing procedure in both cases (when the number of elements is 7 and when the file finishes and the exception is raised) I think the above code violates DRY principle even if I define a new function and call it once in try block and once in except before break. Any other ordering that I could come up with was either causing an infinite loop or losing the final lines.
I appreciate any comments on handling this issue, as it is not limited to this case and I had faced it in other cases as well.
python file
edited 10 mins ago
200_success
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I have this code that reads a file and after processing a few lines writes the output to a second file:
num_reads = 7
with open('data.txt') as read_file:
with open('new_data.txt', 'w') as write_file:
while (True):
lines =
try: # expect errors if the number of lines in the file are not a multiplication of num_reads
for i in range(num_reads):
lines.append(next(read_file)) # when the file finishes an exception occurs here
#do sutff with the lines (exactly num_reads number of lines)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
except StopIteration: # here we process the (possibly) insufficent last lines
#do stuff with the lines (less that num_reads)
processed = " ".join(list(map(lambda x: x.replace("n", ''), lines)))
write_file.write(processed + 'n')
break
Here is the input file (data.txt):
line1
line2
line3
line4
line5
line7
line8
line9
And this is the output file that has the desired state:
line1 line2 line3 line4 line5 line7
line8 line9
This works correctly but as I wish to do the same processing and writing procedure in both cases (when the number of elements is 7 and when the file finishes and the exception is raised) I think the above code violates DRY principle even if I define a new function and call it once in try block and once in except before break. Any other ordering that I could come up with was either causing an infinite loop or losing the final lines.
I appreciate any comments on handling this issue, as it is not limited to this case and I had faced it in other cases as well.
python file
python file
edited 10 mins ago
200_success
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 10 mins ago
200_success
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 10 mins ago
200_success
129k15152415
edited 10 mins ago
200_success
129k15152415
edited 10 mins ago
200_success
129k15152415
129k15152415
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
asked 2 hours ago
Farzad VertigoFarzad Vertigo
1084
1084
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Farzad Vertigo is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago
add a comment |
$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago
$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Disclaimer: This question belongs to Stack Overflow, and I voted to migrate it. Therefore, the answer is not a review.
Keep in mind that principles are there to guide you. They should be treated like guard rails, rather than roadblocks.
I would argue that
while (....) {
foo(7);
}
foo(3);
does not violate DRY. Your situation is pretty much the same.
That said, your idea of defining function is valid. You just factoring out the wrong code. Factor out reading. Consider
def read_n_lines(infile, n):
lines =
try:
for _ in range(n):
lines.append(next(infile))
except StopIteration:
pass
return lines
and use it as
while True:
lines = read_n_lines(infile, 7)
if len(lines) == 0:
break
process_lines(lines)
answered 47 mins ago
vnpvnp
38.9k13098
$endgroup$
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
add a comment |
Your Answer
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Disclaimer: This question belongs to Stack Overflow, and I voted to migrate it. Therefore, the answer is not a review.
Keep in mind that principles are there to guide you. They should be treated like guard rails, rather than roadblocks.
I would argue that
while (....) {
foo(7);
}
foo(3);
does not violate DRY. Your situation is pretty much the same.
That said, your idea of defining function is valid. You just factoring out the wrong code. Factor out reading. Consider
def read_n_lines(infile, n):
lines =
try:
for _ in range(n):
lines.append(next(infile))
except StopIteration:
pass
return lines
and use it as
while True:
lines = read_n_lines(infile, 7)
if len(lines) == 0:
break
process_lines(lines)
answered 47 mins ago
vnpvnp
38.9k13098
$endgroup$
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
add a comment |
$begingroup$
Disclaimer: This question belongs to Stack Overflow, and I voted to migrate it. Therefore, the answer is not a review.
Keep in mind that principles are there to guide you. They should be treated like guard rails, rather than roadblocks.
I would argue that
while (....) {
foo(7);
}
foo(3);
does not violate DRY. Your situation is pretty much the same.
That said, your idea of defining function is valid. You just factoring out the wrong code. Factor out reading. Consider
def read_n_lines(infile, n):
lines =
try:
for _ in range(n):
lines.append(next(infile))
except StopIteration:
pass
return lines
and use it as
while True:
lines = read_n_lines(infile, 7)
if len(lines) == 0:
break
process_lines(lines)
answered 47 mins ago
vnpvnp
38.9k13098
$endgroup$
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
add a comment |
$begingroup$
Disclaimer: This question belongs to Stack Overflow, and I voted to migrate it. Therefore, the answer is not a review.
Keep in mind that principles are there to guide you. They should be treated like guard rails, rather than roadblocks.
I would argue that
while (....) {
foo(7);
}
foo(3);
does not violate DRY. Your situation is pretty much the same.
That said, your idea of defining function is valid. You just factoring out the wrong code. Factor out reading. Consider
def read_n_lines(infile, n):
lines =
try:
for _ in range(n):
lines.append(next(infile))
except StopIteration:
pass
return lines
and use it as
while True:
lines = read_n_lines(infile, 7)
if len(lines) == 0:
break
process_lines(lines)
answered 47 mins ago
vnpvnp
38.9k13098
$endgroup$
Disclaimer: This question belongs to Stack Overflow, and I voted to migrate it. Therefore, the answer is not a review.
Keep in mind that principles are there to guide you. They should be treated like guard rails, rather than roadblocks.
I would argue that
while (....) {
foo(7);
}
foo(3);
does not violate DRY. Your situation is pretty much the same.
That said, your idea of defining function is valid. You just factoring out the wrong code. Factor out reading. Consider
def read_n_lines(infile, n):
lines =
try:
for _ in range(n):
lines.append(next(infile))
except StopIteration:
pass
return lines
and use it as
while True:
lines = read_n_lines(infile, 7)
if len(lines) == 0:
break
process_lines(lines)
answered 47 mins ago
vnpvnp
38.9k13098
answered 47 mins ago
vnpvnp
38.9k13098
answered 47 mins ago
vnpvnp
38.9k13098
answered 47 mins ago
vnpvnp
38.9k13098
38.9k13098
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
add a comment |
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
$begingroup$
Thank you very much. Beautiful idea. I appreciate it.
$endgroup$
– Farzad Vertigo
42 mins ago
add a comment |
Farzad Vertigo is a new contributor. Be nice, and check out our Code of Conduct.
Farzad Vertigo is a new contributor. Be nice, and check out our Code of Conduct.
Farzad Vertigo is a new contributor. Be nice, and check out our Code of Conduct.
Farzad Vertigo is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
Welcome to Code Review! Please tell us in more detail what task this code accomplishes, ideally with example input and output files. Also retitle the question to state the purpose of the code, rather than your concern about the code. See How to Ask.
$endgroup$
– 200_success
1 hour ago
$begingroup$
@200_success done! :)
$endgroup$
– Farzad Vertigo
1 hour ago