Optimize the for loop in python - python

Good, I currently have the following code:
n = 0
with open('/home/user/test.filter') as f:
lines = f.readlines()
for l in lines:
if lines[n].startswith('-A vlan_8'):
if "-o bond1.8" in lines[n]:
f = open('vlan8.filter_in', 'a')
f.write(l)
else:
f = open('vlan8.filter_out', 'a')
f.write(l)
if lines[n].startswith('-A vlan_10'):
if "-o bond1.10" in lines[n]:
f = open('vlan10.filter_in', 'a')
f.write(l)
else:
f = open('vlan10.filter_out', 'a')
f.write(l)
if lines[n].startswith('-A vlan_15'):
if "-o bond1.15" in lines[n]:
f = open('vlan15.filter_in', 'a')
f.write(l)
else:
f = open('vlan15.filter_out', 'a')
f.write(l)
# [...]
n = n + 1
I thought about optimizing it with some accumulator or list to not make the script so extensive. Any suggestions?

Sure you can. Maintain a list of these numbers as so:
numList = [8, 10, 15, ...]
Now, all you need is a little string formatting.
with open('/home/user/test.filter') as f:
lines = f.readlines()
for i, l in enumerate(lines): # I've used enumerate to eliminate n but really you don't need it
for num in numList:
if l.startswith('-A vlan_%d' %num):
if "-o bond1.%d" %num in l:
f = open('vlan%d.filter_in' %num, 'a')
else:
f = open('vlan%d.filter_out' %num, 'a')
f.write(l)
f.close()
break

I think you want to make the code cleaner, not faster. If that is so maybe this would work:
import re
parameter_re = re.compile(r'^-A vla_(\d+).*')
with open('data.csv') as f:
lines = f.readlines()
for line in lines:
# Match required parameter
match = parameter_re.match(line)
# Skip line if it doesn't match the required parameter
if not match:
continue
# Extract number from parameter
number = int(match.group(1))
# Create output parameter string
output_str = '-o bond1.%d' % number
# Select correct filename to save the line
if output_str in line:
output_filename = 'vlan%d.filter_in' % number
else:
output_filename = 'vlan%d.filter_out' % number
# Write the line to the correct file
with open(output_filename, 'a') as f:
f.write(line)
And if you want to make it shorter (which I don't recommend, better for it to be readable):
import re
with open('data.csv') as f:
lines = f.readlines()
for line in lines:
match = re.match(r'^-A vla_(\d+).*', line)
if not match:
continue
number = int(match.group(1))
if '-o bond1.%d' % number in line:
output_filename = 'vlan%d.filter_in' % number
else:
output_filename = 'vlan%d.filter_out' % number
with open(output_filename, 'a') as f:
f.write(line)

Related

Finding desired search result from list in Txt file with python

def add():
while True:
try:
a = int(input("How many words do you want to add:"))
if a >= 0:
break
else:
raise ValueError
except ValueError:
print("Not valid ")
return a
for i in range(add()):
key_i = input(f"Turkish meaning: {i + 1}: ")
value_i = input("translated version: ")
with open('words.txt', 'a+') as f:
f.write("'"+key_i+':')+ f.write(value_i+"'"+",")
My goal is to create my own dictionary,but I am adding a list into the txt file, so it is added into the txt file like this
words = {'araba:kol',
but when I search the txt file it gives me the whole list
def search():
while 1:
search = str(input("Search: "))
if search not in["exit", "Exit"]:
with open('words.txt', 'r+') as f:
line = f.readline()
while line:
data = line.find(search)
if not data == -1:
print(line.rstrip('\n'))
line = f.readline()
else:
line = f.readline()
else:
break
f.close()
What can I do to make it output like this
car:araba
Use JSON module to avoid having to write the dictionary line by line yourself.
import json
with open('words.json', 'a+') as f:
json.dump({key_i: value_i}, f)
with open('data.json', 'r') as f:
d2 = json.load(f)
d2 is now the data that you wrote to the file.
Note, that you should change the a+ to 'w' as you only have one dictionary per file.

How to format list in text file?

I have a text file like below
Mo, M, 15,
Jen, F, 14
My code below replaces the age for 'Mo'
newAge = "20"
result = ""
with open("file.txt") as f:
for line in f:
if line.lower().startswith( "mo," ):
list = line.split()
list[2] = str( newAge )
line = ", ".join( list )
result += line + '\n'
f = open("file.txt", 'w')
f.write(result)
f.close()
How ever the file afterwards look like
[,',,M,,o,,M,,2,,0,,',]
How to I format it to look like the:
Mo, M, 20,
Use the csv module for both reading and writing the file. Below is a tested example.
newAge = ' 20'
result = []
with open('file.txt','rb') as fin, open('file_out.txt','wb') as fou:
cr = csv.reader(fin)
cw = csv.writer(fou)
for line in cr:
if line[0].lower() == "mo":
line[2] = newAge
cw.writerow(line)
You could try this instead:
newAge = "20"
result = ""
with open("file.txt") as f:
for line in f:
if line.lower().startswith( "mo," ):
list = line.split()
list[2] = newAge
line = ''
for element in list:
line += str(element)
line += ', '
result += line + '\n'
with open('file.txt', 'w') as inf:
inf.write(result)
If you're particular about the space at the end of the last element, you could even do:
newAge = "20"
result = ""
with open("file.txt") as f:
for line in f:
if line.lower().startswith( "mo," ):
list = line.split()
list[2] = newAge
line = ''
for index, element in enumerate(list):
line += str(element)
if not index is len(list) -1:
line += ', '
else:
line += ','
result += line + '\n'
with open('file.txt', 'w') as inf:
inf.write(result)
like #azalea mentioned, use .split(', '). Also, you should only use the newline character on strings you build because the existing strings already contain the new line.
newAge = "20"
result = ""
with open("file.txt") as f:
for line in f:
if line.lower().startswith("mo"):
list = line.split(', ')
list[2] = str(newAge)
line = ", ".join(list) + '\n'
result += line
f = open("file2.txt", 'w')
f.write(result)
f.close()
You split the line by space...then you should join it by space!
newAge = "20"
result = ""
with open("file.txt") as f:
for line in f:
if line.lower().startswith( "mo," ):
list = line.split()
list[2] = str( newAge )
line = " ".join( list )+"\n"
result += line
f = open("file.txt", 'w')
f.write(result)
f.close()
I prefer using keeping it simple . Just use the string module.
You can use it in this way.
import string
toFind = '15'
newAge = '20'
with open('file.txt','r') as f:
text = f.readlines()
text[0] = string.replace(text[0],toFind,newAge)
with open('file.txt','w') as f:
for item in text:
f.write(item)
I hope this helps!

Python replace value in text file

I'm trying to replace a value in a specific line in a text file.
My text file contains count of the searchterm, searchterm & date and time
Text file:
MemTotal,5,2016-07-30 12:02:33,781
model name,3,2016-07-30 13:37:59,074
model,3,2016-07-30 15:39:59,075
How can I replace for example the count of the searchterm for line 2 (model name,3,2016-07-30 13:37:59,074)?
This is what I have already:
f = open('file.log','r')
filedata = f.read()
f.close()
newdata = filedata.replace("2", "3")
f = open('file.log', 'w')
f.write(newdata)
f.close()
It replace all values 2.
You have to change three things in your code to get the job done:
Read the file using readlines.
filedata = f.readlines()
Modify the line you want to change (keep in mind that Python indices start at 0 and don't forget to add a newline character \n at the end of the string):
filedata[1] = 'new count,new search term,new date and time\n'
Save the file using a for loop:
for line in filedata:
f.write(line)
Here is the full code (notice I used the with context manager to open/close the file):
with open('file.log', 'r') as f:
filedata = f.readlines()
filedata[1] = 'new count,new search term,new date and time\n'
with open('file.log', 'w') as f:
for line in filedata:
f.write(line)
My solution:
count = 0
line_number = 0
replace = ""
f = open('examen.log','r')
term = "MemTotal"
for line in f.read().split('\n'):
if term in line:
replace= line.replace("5", "25", 1)
line_number = count
count = count + 1
print line_number
f.close()
f = open('examen.log','r')
filedata = f.readlines()
f.close()
filedata[line_number]=replace+'\n'
print filedata[line_number]
print filedata
f = open('examen.log','w')
for line in filedata:
f.write(line)
f.close()
You only need to define the searchterm & the replace value

Get all the lines below certain words, until there's a space [duplicate]

Lets say I have a Text file with the below content
fdsjhgjhg
fdshkjhk
Start
Good Morning
Hello World
End
dashjkhjk
dsfjkhk
Now I need to write a Python code which will read the text file and copy the contents between Start and end to another file.
I wrote the following code.
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer = []
keepCurrentSet = True
for line in inFile:
buffer.append(line)
if line.startswith("Start"):
#---- starts a new data set
if keepCurrentSet:
outFile.write("".join(buffer))
#now reset our state
keepCurrentSet = False
buffer = []
elif line.startswith("End"):
keepCurrentSet = True
inFile.close()
outFile.close()
I'm not getting the desired output as expected
I'm just getting Start
What I want to get is all the lines between Start and End.
Excluding Start & End.
Just in case you have multiple "Start"s and "End"s in your text file, this will import all the data together, excluding all the "Start"s and "End"s.
with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
copy = False
for line in infile:
if line.strip() == "Start":
copy = True
continue
elif line.strip() == "End":
copy = False
continue
elif copy:
outfile.write(line)
If the text files aren't necessarily large, you can get the whole content of the file then use regular expressions:
import re
with open('data.txt') as myfile:
content = myfile.read()
text = re.search(r'Start\n.*?End', content, re.DOTALL).group()
with open("result.txt", "w") as myfile2:
myfile2.write(text)
I'm not a Python expert, but this code should do the job.
inFile = open("data.txt")
outFile = open("result.txt", "w")
keepCurrentSet = False
for line in inFile:
if line.startswith("End"):
keepCurrentSet = False
if keepCurrentSet:
outFile.write(line)
if line.startswith("Start"):
keepCurrentSet = True
inFile.close()
outFile.close()
Using itertools.dropwhile, itertools.takewhile, itertools.islice:
import itertools
with open('data.txt') as f, open('result.txt', 'w') as fout:
it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
it = itertools.islice(it, 1, None)
it = itertools.takewhile(lambda line: line.strip() != 'End', it)
fout.writelines(it)
UPDATE: As inspectorG4dget commented, above code copies over the first block. To copy multiple blocks, use following:
import itertools
with open('data.txt', 'r') as f, open('result.txt', 'w') as fout:
while True:
it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
if next(it, None) is None: break
fout.writelines(itertools.takewhile(lambda line: line.strip() != 'End', it))
Move the outFile.write call into the 2nd if:
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer = []
for line in inFile:
if line.startswith("Start"):
buffer = ['']
elif line.startswith("End"):
outFile.write("".join(buffer))
buffer = []
elif buffer:
buffer.append(line)
inFile.close()
outFile.close()
import re
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer1 = ""
keepCurrentSet = True
for line in inFile:
buffer1=buffer1+(line)
buffer1=re.findall(r"(?<=Start) (.*?) (?=End)", buffer1)
outFile.write("".join(buffer1))
inFile.close()
outFile.close()
I would handle it like this :
inFile = open("data.txt")
outFile = open("result.txt", "w")
data = inFile.readlines()
outFile.write("".join(data[data.index('Start\n')+1:data.index('End\n')]))
inFile.close()
outFile.close()
if one wants to keep the start and end lines/keywords while extracting the lines between 2 strings.
Please find below the code snippet that I used to extract sql statements from a shell script
def process_lines(in_filename, out_filename, start_kw, end_kw):
try:
inp = open(in_filename, 'r', encoding='utf-8', errors='ignore')
out = open(out_filename, 'w+', encoding='utf-8', errors='ignore')
except FileNotFoundError as err:
print(f"File {in_filename} not found", err)
raise
except OSError as err:
print(f"OS error occurred trying to open {in_filename}", err)
raise
except Exception as err:
print(f"Unexpected error opening {in_filename} is", repr(err))
raise
else:
with inp, out:
copy = False
for line in inp:
# first IF block to handle if the start and end on same line
if line.lstrip().lower().startswith(start_kw) and line.rstrip().endswith(end_kw):
copy = True
if copy: # keep the starts with keyword
out.write(line)
copy = False
continue
elif line.lstrip().lower().startswith(start_kw):
copy = True
if copy: # keep the starts with keyword
out.write(line)
continue
elif line.rstrip().endswith(end_kw):
if copy: # keep the ends with keyword
out.write(line)
copy = False
continue
elif copy:
# write
out.write(line)
if __name__ == '__main__':
infile = "/Users/testuser/Downloads/testdir/BTEQ_TEST.sh"
outfile = f"{infile}.sql"
statement_start_list = ['database', 'create', 'insert', 'delete', 'update', 'merge', 'delete']
statement_end = ";"
process_lines(infile, outfile, tuple(statement_start_list), statement_end)
Files are iterators in Python, so this means you don't need to hold a "flag" variable to tell you what lines to write. You can simply use another loop when you reach the start line, and break it when you reach the end line:
with open("data.txt") as in_file, open("result.text", 'w') as out_file:
for line in in_file:
if line.strip() == "Start":
for line in in_file:
if line.strip() == "End":
break
out_file.write(line)

Extract Values between two strings in a text file using python

Lets say I have a Text file with the below content
fdsjhgjhg
fdshkjhk
Start
Good Morning
Hello World
End
dashjkhjk
dsfjkhk
Now I need to write a Python code which will read the text file and copy the contents between Start and end to another file.
I wrote the following code.
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer = []
keepCurrentSet = True
for line in inFile:
buffer.append(line)
if line.startswith("Start"):
#---- starts a new data set
if keepCurrentSet:
outFile.write("".join(buffer))
#now reset our state
keepCurrentSet = False
buffer = []
elif line.startswith("End"):
keepCurrentSet = True
inFile.close()
outFile.close()
I'm not getting the desired output as expected
I'm just getting Start
What I want to get is all the lines between Start and End.
Excluding Start & End.
Just in case you have multiple "Start"s and "End"s in your text file, this will import all the data together, excluding all the "Start"s and "End"s.
with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
copy = False
for line in infile:
if line.strip() == "Start":
copy = True
continue
elif line.strip() == "End":
copy = False
continue
elif copy:
outfile.write(line)
If the text files aren't necessarily large, you can get the whole content of the file then use regular expressions:
import re
with open('data.txt') as myfile:
content = myfile.read()
text = re.search(r'Start\n.*?End', content, re.DOTALL).group()
with open("result.txt", "w") as myfile2:
myfile2.write(text)
I'm not a Python expert, but this code should do the job.
inFile = open("data.txt")
outFile = open("result.txt", "w")
keepCurrentSet = False
for line in inFile:
if line.startswith("End"):
keepCurrentSet = False
if keepCurrentSet:
outFile.write(line)
if line.startswith("Start"):
keepCurrentSet = True
inFile.close()
outFile.close()
Using itertools.dropwhile, itertools.takewhile, itertools.islice:
import itertools
with open('data.txt') as f, open('result.txt', 'w') as fout:
it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
it = itertools.islice(it, 1, None)
it = itertools.takewhile(lambda line: line.strip() != 'End', it)
fout.writelines(it)
UPDATE: As inspectorG4dget commented, above code copies over the first block. To copy multiple blocks, use following:
import itertools
with open('data.txt', 'r') as f, open('result.txt', 'w') as fout:
while True:
it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
if next(it, None) is None: break
fout.writelines(itertools.takewhile(lambda line: line.strip() != 'End', it))
Move the outFile.write call into the 2nd if:
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer = []
for line in inFile:
if line.startswith("Start"):
buffer = ['']
elif line.startswith("End"):
outFile.write("".join(buffer))
buffer = []
elif buffer:
buffer.append(line)
inFile.close()
outFile.close()
import re
inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer1 = ""
keepCurrentSet = True
for line in inFile:
buffer1=buffer1+(line)
buffer1=re.findall(r"(?<=Start) (.*?) (?=End)", buffer1)
outFile.write("".join(buffer1))
inFile.close()
outFile.close()
I would handle it like this :
inFile = open("data.txt")
outFile = open("result.txt", "w")
data = inFile.readlines()
outFile.write("".join(data[data.index('Start\n')+1:data.index('End\n')]))
inFile.close()
outFile.close()
if one wants to keep the start and end lines/keywords while extracting the lines between 2 strings.
Please find below the code snippet that I used to extract sql statements from a shell script
def process_lines(in_filename, out_filename, start_kw, end_kw):
try:
inp = open(in_filename, 'r', encoding='utf-8', errors='ignore')
out = open(out_filename, 'w+', encoding='utf-8', errors='ignore')
except FileNotFoundError as err:
print(f"File {in_filename} not found", err)
raise
except OSError as err:
print(f"OS error occurred trying to open {in_filename}", err)
raise
except Exception as err:
print(f"Unexpected error opening {in_filename} is", repr(err))
raise
else:
with inp, out:
copy = False
for line in inp:
# first IF block to handle if the start and end on same line
if line.lstrip().lower().startswith(start_kw) and line.rstrip().endswith(end_kw):
copy = True
if copy: # keep the starts with keyword
out.write(line)
copy = False
continue
elif line.lstrip().lower().startswith(start_kw):
copy = True
if copy: # keep the starts with keyword
out.write(line)
continue
elif line.rstrip().endswith(end_kw):
if copy: # keep the ends with keyword
out.write(line)
copy = False
continue
elif copy:
# write
out.write(line)
if __name__ == '__main__':
infile = "/Users/testuser/Downloads/testdir/BTEQ_TEST.sh"
outfile = f"{infile}.sql"
statement_start_list = ['database', 'create', 'insert', 'delete', 'update', 'merge', 'delete']
statement_end = ";"
process_lines(infile, outfile, tuple(statement_start_list), statement_end)
Files are iterators in Python, so this means you don't need to hold a "flag" variable to tell you what lines to write. You can simply use another loop when you reach the start line, and break it when you reach the end line:
with open("data.txt") as in_file, open("result.text", 'w') as out_file:
for line in in_file:
if line.strip() == "Start":
for line in in_file:
if line.strip() == "End":
break
out_file.write(line)

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