I want to find the lines which start with a word of a list. If the word is found i want the line it stands in and the previous line to be deleted.
I am able to get the line and the previos one and print them but i can not get my head around not to pass them to my outputfile.
F.e.:
in-put:
This is not supposed to be deleted.
This shall be deleted.
Titel
This is not supposed to be deleted.
This is not supposed to be deleted
out-put:
This is not supposed to be deleted.
This is not supposed to be deleted.
This is not supposed to be deleted
I tried it with this code, but i keep getting a TypeError: 'str' object does not support item assignment
with open(file1) as f_in, open(file2, 'w') as f_out:
lines = f_in.read().splitlines()
for i, line in enumerate(lines):
clean = True
if line.startswith(('Text', 'Titel')):
for (line[i-1]) in lines:
clean = False
for line in lines:
clean =False
if clean == True:
f_out.write(line)
You don't have to read the file at once. Read the lines after each other, and store the current line, but write it out only after the next read, or not.
with open("file1") as finp, open("file2","w") as fout:
lprev=""
for line in finp:
if line.startswith("Titel") or line.startswith("Text"):
lprev=""
continue
if lprev:
fout.write(lprev)
lprev=line
if lprev:
fout.write(lprev) # write out the last line if needed
First keep track of which lines you want to copy:
lines_to_keep = []
with open(file1) as f_in:
deleted_previous_line = True
for line in f_in:
if line.startswith(('Text', 'Titel')):
if not deleted_previous_line:
del lines_to_keep[-1]
deleted_previous_line = True
continue
deleted_previous_line = False
lines_to_keep.append(line)
The trick with the deleted_previous_line is necessary to ensure it does not delete too many lines if consecutive lines start with 'Text' or 'Titel'.
Then write it to your output file
with open(file2, 'w') as f_out:
f_out.writelines(lines_to_keep)
Related
How you can implement deleting lines in a text document up to a certain line?
I find the line number using the code:
#!/usr/bin/env python
lookup = '00:00:00'
filename = "test.txt"
with open(filename) as text_file:
for num, line in enumerate(text_file, 1):
if lookup in line:
print(num)
print(num) outputs me the value of the string, for example 66.
How do I delete all the lines up to 66, i.e. up to the found line by word?
As proposed here with a small modification to your case:
read all lines of the file.
iterate the lines list until you reach the keyword.
write all remaining lines
with open("yourfile.txt", "r") as f:
lines = iter(f.readlines())
with open("yourfile.txt", "w") as f:
for line in lines:
if lookup in line:
f.write(line)
break
for line in lines:
f.write(line)
That's easy.
filename = "test.txt"
lookup = '00:00:00'
with open(filename,'r') as text_file:
lines = text_file.readlines()
res=[]
for i in range(0,len(lines),1):
if lookup in lines[i]:
res=lines[i:]
break
with open(filename,'w') as text_file:
text_file.writelines(res)
Do you know what lines you want to delete?
#!/usr/bin/env python
lookup = '00:00:00'
filename = "test.txt"
with open(filename) as text_file, open('okfile.txt', 'w') as ok:
lines = text_file.readlines()
ok.writelines(lines[4:])
This will delete the first 4 lines and store them in a different document in case you wanna keep the original.
Remember to close the files when you're done with them :)
Providing three alternate solutions. All begin with the same first part - reading:
filename = "test.txt"
lookup = '00:00:00'
with open(filename) as text_file:
lines = text_file.readlines()
The variations for the second parts are:
Using itertools.dropwhile which discards items from the iterator until the predicate (condition) returns False (ie discard while predicate is True). And from that point on, yields all the remaining items without re-checking the predicate:
import itertools
with open(filename, 'w') as text_file:
text_file.writelines(itertools.dropwhile(lambda line: lookup not in line, lines))
Note that it says not in. So all the lines before lookup is found, are discarded.
Bonus: If you wanted to do the opposite - write lines until you find the lookup and then stop, replace itertools.dropwhile with itertools.takewhile.
Using a flag-value (found) to determine when to start writing the file:
with open(filename, 'w') as text_file:
found = False
for line in lines:
if not found and lookup in line: # 2nd expression not checked once `found` is True
found = True # value remains True for all remaining iterations
if found:
text_file.write(line)
Similar to #c yj's answer, with some refinements - use enumerate instead of range, and then use the last index (idx) to write the lines from that point on; with no other intermediate variables needed:
for idx, line in enumerate(lines):
if lookup in line:
break
with open(filename, 'w') as text_file:
text_file.writelines(lines[idx:])
I have the following problem. I am supposed to open a CSV file (its an excel table) and read it without using any library.
I tried already a lot and have now the first row in a tuple and this in a list. But only the first line. The header. But no other row.
This is what I have so far.
with open(path, 'r+') as file:
results=[]
text = file.readline()
while text != '':
for line in text.split('\n'):
a=line.split(',')
b=tuple(a)
results.append(b)
return results
The output should: be every line in a tuple and all the tuples in a list.
My question is now, how can I read the other lines in python?
I am really sorry, I am new to programming all together and so I have a real hard time finding my mistake.
Thank you very much in advance for helping me out!
This problem was many times on Stackoverflow so you should find working code.
But much better is to use module csv for this.
You have wrong indentation and you use return results after reading first line so it exits function and it never try read other lines.
But after changing this there are still other problems so it still will not read next lines.
You use readline() so you read only first line and your loop will works all time with the same line - and maybe it will never ends because you never set text = ''
You should use read() to get all text which later you split to lines using split("\n") or you could use readlines() to get all lines as list and then you don't need split(). OR you can use for line in file: In all situations you don't need while
def read_csv(path):
with open(path, 'r+') as file:
results = []
text = file.read()
for line in text.split('\n'):
items = line.split(',')
results.append(tuple(items))
# after for-loop
return results
def read_csv(path):
with open(path, 'r+') as file:
results = []
lines = file.readlines()
for line in lines:
line = line.rstrip('\n') # remove `\n` at the end of line
items = line.split(',')
results.append(tuple(items))
# after for-loop
return results
def read_csv(path):
with open(path, 'r+') as file:
results = []
for line in file:
line = line.rstrip('\n') # remove `\n` at the end of line
items = line.split(',')
results.append(tuple(items))
# after for-loop
return results
All this version will not work correctly if you will '\n' or , inside item which shouldn't be treated as end of row or as separtor between items. These items will be in " " which also can make problem to remove them. All these problem you can resolve using standard module csv.
Your code is pretty well and you are near goal:
with open(path, 'r+') as file:
results=[]
text = file.read()
#while text != '':
for line in text.split('\n'):
a=line.split(',')
b=tuple(a)
results.append(b)
return results
Your Code:
with open(path, 'r+') as file:
results=[]
text = file.readline()
while text != '':
for line in text.split('\n'):
a=line.split(',')
b=tuple(a)
results.append(b)
return results
So enjoy learning :)
One caveat is that the csv may not end with a blank line as this would result in an ugly tuple at the end of the list like ('',) (Which looks like a smiley)
To prevent this you have to check for empty lines: if line != '': after the for will do the trick.
guess you have a solution concerning the following issue:
I want to compare two lists for common entries (on the basis of column 10) and write common entries to one file and unique entries for the first list into another file. The code I wrote is:
INFILE1 = open ("c:\\python\\test\\58962.filtered.csv", "r")
INFILE2 = open ("c:\\python\\test\\83887.filtered.csv", "r")
OUTFILE1 = open ("c:\\python\\test\\58962_vs_83887.common.csv", "w")
OUTFILE2 = open ("c:\\python\\test\\58962_vs_83887.unique.csv", "w")
for line in INFILE1:
line = line.rstrip().split(",")
if line[11] in INFILE2:
OUTFILE1.write(line)
else:
OUTFILE2.write(line)
INFILE1.close()
INFILE2.close()
OUTFILE1.close()
OUTFILE2.close()
The following error appears:
8 OUTFILE1.write(line)
9 else:
---> 10 OUTFILE2.write(line)
11 INFILE1.close()
TypeError: write() argument must be str, not list
Does somebody know about help for this?
Best
This line
line = line.rstrip().split(",")
replaces the line you read from a file by it's splitted list. You then try to write the splitted list to your file - thats not how the write method works and it tells you exactly that.
Change it to :
for line in INFILE1:
lineList = line.rstrip().split(",") # dont overwrite line, use lineList
if lineList[11] in INFILE2: # used lineList
OUTFILE1.write(line) # corrected indentation
else:
OUTFILE2.write(line)
You could have easily found your error yourself, just printing out the line before and after splitting or just befrore writing.
Please read How to debug small programs (#1) and follow it - its easier to find and fix bugs yourself then posting questions here.
You have some other problem at hand, though:
Files are stream based, they start with a position of 0 in the file. The position is advanced if you access parts of the file. When at the end, you wont get anything by using INFILE2.read() or other methods.
So if you want to repeatadly check if some lines column of file1 is somewhere in file2 you need to read file2 into a list (or other datastructure) so your repeated checks work. In other words, this:
if lineList[11] in INFILE2:
might work once, then the file is consumed and it will return false all the time.
You also might want to change from:
f = open(...., ...)
# do something with f
f.close()
to
with open(name,"r") as f:
# do something with f, no close needed, closed when leaving block
as it is safer, will close the file even if exceptions happen.
To solve that try this (untested) code:
with open ("c:\\python\\test\\83887.filtered.csv", "r") as file2:
infile2 = file2.readlines() # read in all lines as list
with open ("c:\\python\\test\\58962.filtered.csv", "r") as INFILE1:
# next 2 lines are 1 line, \ at end signifies line continues
with open ("c:\\python\\test\\58962_vs_83887.common.csv", "w") as OUTFILE1, \
with open ("c:\\python\\test\\58962_vs_83887.unique.csv", "w") as OUTFILE2:
for line in INFILE1:
lineList = line.rstrip().split(",")
if any(lineList[11] in x for x in infile2): # check the list of lines if
# any contains line[11]
OUTFILE1.write(line)
else:
OUTFILE2.write(line)
# all files are autoclosed here
Links to read:
the-with-statement
any() and other built-ins
I want to open a file, search for a specific word, change the word and save the file again. Sounds really easy - but I just can't get it working... I know that I have to overwrite the whole file but only change this one word!
My Code:
f = open('./myfile', 'r')
linelist = f.readlines()
f.close
for line in linelist:
i =0;
if 'word' in line:
for number in arange(0,1,0.1)):
myNumber = 2 - number
myNumberasString = str(myNumber)
myChangedLine = line.replace('word', myNumberasString)
f2 = open('./myfile', 'w')
f2.write(line)
f2.close
#here I have to do some stuff with these files so there is a reason
#why everything is in this for loop. And I know that it will
#overwrite the file every loop and that is good so. I want that :)
If I make it like this, the 'new' myfile file contains only the changed line. But I want the whole file with the changed line... Can anyone help me?
****EDIT*****
I fixed it! I just turned the loops around and now it works perfectly like this:
f=open('myfile','r')
text = f.readlines()
f.close()
i =0;
for number in arange(0,1,0.1):
fw=open('mynewfile', 'w')
myNumber = 2 - number
myNumberasString = str(myNumber)
for line in text:
if 'word' in line:
line = line.replace('word', myNumberasString)
fw.write(line)
fw.close()
#do my stuff here where I need all these input files
You just need to write out all the other lines as you go. As I said in my comment, I don't know what you are really trying to do with your replace, but here's a slightly simplified version in which we're just replacing all occurrences of 'word' with 'new':
f = open('./myfile', 'r')
linelist = f.readlines()
f.close
# Re-open file here
f2 = open('./myfile', 'w')
for line in linelist:
line = line.replace('word', 'new')
f2.write(line)
f2.close()
Or using contexts:
with open('./myfile', 'r') as f:
lines = f.readlines()
with open('./myfile', 'w') as f:
for line in lines:
line = line.replace('word', 'new')
f.write(line)
Use fileinput passing in whatever you want to replace:
import fileinput
for line in fileinput.input("in.txt",inplace=True):
print(line.replace("whatever","foo"),end="")
You don't seem to be doing anything special in your loop that cannot be calculated first outside the loop, so create the string you want to replace the word with and pass it to replace.
inplace=True will mean the original file is changed. If you want to verify everything looks ok then remove the inplace=True for the first run and you will actually see the replaced output instead of the lines being written to the file.
If you want to write to a temporary file, you can use a NamedTemporaryFile with shutil.move:
from tempfile import NamedTemporaryFile
from shutil import move
with open("in.txt") as f, NamedTemporaryFile(dir=".",delete=False) as out:
for line in f:
out.write(line.replace("whatever","foo"))
move("in.txt",out.name)
One problem you may encounter is matching substrings with replace so if you know the word is always followed in the middle of a sentence surrounded by whitespace you could add that but if not you will need to split and check every word.
from tempfile import NamedTemporaryFile
from shutil import move
from string import punctuation
with open("in.txt") as f, NamedTemporaryFile(dir=".",delete=False) as out:
for line in f:
out.write(" ".join(word if word.strip(punctuation) != "whatever" else "foo"
for word in line.split()))
The are three issues with your current code. First, create the f2 file handle before starting the loop, otherwise you'll overwrite the file in each iteration. Third, you are writing an unmodified line in f2.write(line). I guess you meant f2.write(myChangedLine)? Third, you should add an else statement that writes unmodified lines to the file. So:
f = open('./myfile', 'r')
linelist = f.readlines()
f.close
f2 = open('./myfile', 'w')
for line in linelist:
i =0;
if 'word' in line:
for number in arange(0,1,0.1)):
myNumber = 2 - number
myNumberasString = str(myNumber)
myChangedLine = line.replace('word', myNumberasString)
f2.write(myChangedLine)
else:
f2.write(line)
f2.close()
How do you skip to the next lines of a file being looped line by line. This code below is skipping lines for the total count in the 2nd loop, I want it to skip the line 1 by 1 for the desired count so I can pull the right information from the file.
f = open("someTXT", "r")
lines = iter(f.readlines())
for line in lines:
thisLine = line.split(',')
if len(thisLine) > 3:
count = thisLine[4]
for i in range(1,int(count)):
next(lines)
print(line)
Here's a bit of code review. Not sure what you're asking though.
Use the context manager to open files:
with open("someTXT", 'rU') as f: # Universal newline flag, best practice
# lines = iter(f) # no need for this, my_file is an iterator
container = [] # use a container to hold your lines
for line in f:
test = test_for_correct_lines(line) # return True if keep and print
if test:
container.append(line)
# join the lines you want to keep with a newline and print them
print('\n'.join(container))