Goal is to replace 'byebye' with 'Hello '
# START: file.txt contains string "byebye World!"
fd = File.open('file.txt', 'a')
fd.seek(0, IO::SEEK_SET)
fd.puts 'Hello '
fd.close
# END: file.txt contains two lines "byebye World " and "Hello "
I understand what exists other excellent ( and working:) ) ways to achieve it, but why that code don't write on right position?
I think you're misunderstanding w+, you may want r+ as the modestring, here's what w+ does.
w+
Read-write, truncates existing file to zero length or creates a new file for reading and writing.
truncate existing file to zero length is eating your string.
Related
I'm having trouble reading an IP from a text file and properly writing it to another text file. It shows the written IP in the file as: "ÿþ1 9 2 . 1 6 8 . 1 1 0 . 4"
#Read the first line for the IP
def get_server_ip
File.open("d:\\ip_addr.txt") do |line|
a = line.readline()
b = a.to_s
end
end
#append the ip to file2
def append_ip
FileUtils.cp('file1.txt', 'file2.txt')
file_names = ['file2.txt']
file_names.each do |file_name|
text = File.read(file_name)
b = get_server_ip
new_contents = text.gsub('ip_here', b)
File.open(file_name, "w") {|file| file.puts new_contents }
end
end
I've tried .strip and .delete(' ') with no luck. Can anyone see the issue?
Thank you
The file was generated with Notepad on Windows. It is encoded as UTF-16LE.
The first two bytes in the file have the codes 0xFF and 0xFE; this is the Bytes Order Mark of UTF-16LE.
Each character is encoded on 2 bytes (16 bits), the least significant byte first (Less Endian order).
The spaces between the printable characters in the output are, in fact NUL characters (characters with code 0).
What you can do (apart from converting the file to a more decent format like UTF-8 or even ISO-8859-1) is to pass 'rb:BOM|UTF-16LE' as the second argument of File#open.
r tells File#open to open the file in read-only mode (which is also does by default);
b means "binary mode"; it is required by BOM|UTF-16;
:BOM|UTF-16LE tells Ruby to read and ignore the BOM if it is present in the file and to expect the rest of the file being encoded as UTF16-LE.
If you can, I recommend you to convert the file encoding using a decent editor (even Notepad can be used) to UTF-8 or ISO-8859-1 and all these problems vanish.
I'm new to python and this site so thank-you in advance for your... understanding. This is my first attempt at a python script.
I'm having what I think is a performance issue trying to solve this problem which is causing me to not get any data back.
This code works on a small text file of a couple pages but when I try to use it on my 35MB real data text file it just hits the CPU and hasn't returned any data (>24 hours now).
Here's a snippet of the real data from the 35MB text file:
D)dddld
d00d90d
dd
ddd
vsddfgsdfgsf
dfsdfdsf
aAAAAAa
221546
29806916295
Meowing
fs:/mod/umbapp/umb/sentbox/221546.pdu
2013:10:4:22:11:31:4
sadfsdfsdf
sdfff
ff
f
29806916295
What's your cat doing?
fs:/mod/umbapp/umb/sentbox/10955.pdu
2013:10:4:22:10:15:4
aaa
aaa
aaaaa
What I'm trying to copy into a new file:
29806916295
Meowing
fs:/mod/umbapp/umb/sentbox/221546.pdu
2013:10:4:22:11:31:4
29806916295
What's your cat doing?
fs:/mod/umbapp/umb/sentbox/10955.pdu
2013:10:4:22:10:15:4
My Python code is:
import re
with open('testdata.txt') as myfile:
content = myfile.read()
text = re.search(r'\d{11}.*\n.*\n.*(\d{4})\D+(\d{2})\D+(\d{1})\D+(\d{2})\D+(\d{2})\D+\d{2}\D+\d{1}', content, re.DOTALL).group()
with open("result.txt", "w") as myfile2:
myfile2.write(text)
Regex isn't the fastest way to search a string. You also compounded the problem by having a very big string (35MB). Reading an entire file into memory is generally not recommended because you may run into memory issues.
Judging from your regex pattern, it seems like you want to capture 4-line groups that start with an 11-digit string and end with some time-line string. Try this code:
import re
start_pattern = re.compile(r'^\d{11}$')
end_pattern = re.compile(r'^\d{4}\D+\d{2}\D+\d{1}\D+\d{2}\D+\d{2}\D+\d{2}\D+\d{1}$')
capturing = 0
capture = ''
with open('output.txt', 'w') as output_file:
with open('input.txt', 'r') as input_file:
for line in input_file:
if capturing > 0 and capturing <= 4:
capturing += 1
capture += line
elif start_pattern.match(line):
capturing = 1
capture = line
if capturing == 4:
if end_pattern.match(line):
output_file.write(capture + '\n')
else:
capturing = 0
It iterates over the input file, line by line. If it finds a line matching the start_pattern, it will read in 3 more. If the 4th line matches the end_pattern, it will write the whole group to the output file.
I'm moving my bookmarks from kippt.com to pinboard.in.
I exported my bookmarks from Kippt and for some reason, they were storing tags (preceded by #) and description within the same field. Pinboard keeps tags and description separated.
This is what a Kippt bookmark looks like after export:
<DT>This is a title
<DD>#tag1 #tag2 This is a description
This is what it should look like before importing into Pinboard:
<DT>This is a title
<DD>This is a description
So basically, I need to replace #tag1 #tag2 by TAGS="tag1,tag2" and move it on the first line within <A>.
I've been reading about moving chunks of data here: sed or awk to move one chunk of text betwen first pattern pair into second pair?
I haven't been to come up with a good recipe so far. Any insight?
Edit:
Here's an actual example of what the input file looks like (3 entries out of 3500):
<DT>Phabricator
<DD>#bug #tracking
<DT>The hidden commands for diagnosing and improving your Netflix streaming quality – Quartz
<DT>Icelandic Farm Holidays | Local experts in Iceland vacations
<DD>#iceland #tour #car #drive #self Self-driving tour of Iceland
This might not be the most beautiful solution, but since it seems to be a one-time-thing it should be sufficient.
import re
dt = re.compile('^<DT>')
dd = re.compile('^<DD>')
with open('bookmarks.xml', 'r') as f:
for line in f:
if re.match(dt, line):
current_dt = line.strip()
elif re.match(dd, line):
current_dd = line
tags = [w for w in line[4:].split(' ') if w.startswith('#')]
current_dt = re.sub('(<A[^>]+)>', '\\1 TAGS="' + ','.join([t[1:] for t in tags]) + '">', current_dt)
for t in tags:
current_dd = current_dd.replace(t + ' ', '')
if current_dd.strip() == '<DD>':
current_dd = ""
else:
print current_dt
print current_dd
current_dt = ""
current_dd = ""
print current_dt
print current_dd
If some parts of the code are not clear, just tell me. You can of course use python to write the lines to a file instead of printing them, or even modify the original file.
Edit: Added if-clause so that empty <DD> lines won't show up in the result.
script.awk
BEGIN{FS="#"}
/^<DT>/{
if(d==1) print "<DT>"s # for printing lines with no tags
s=substr($0,5);tags="" # Copying the line after "<DT>". You'll know why
d=1
}
/^<DD>/{
d=0
m=match(s,/>/) # Find the end of the HREF descritor first match of ">"
for(i=2;i<=NF;i++){sub(/ $/,"",$i);tags=tags","$i} # Concatenate tags
td=match(tags,/ /) # Parse for tag description (marked by a preceding space).
if(td==0){ # No description exists
tags=substr(tags,2)
tagdes=""
}
else{ # Description exists
tagdes=substr(tags,td)
tags=substr(tags,2,td-2)
}
print "<DT>" substr(s,1,m-1) ", TAGS=\"" tags "\"" substr(s,m)
print "<DD>" tagdes
}
awk -f script.awk kippt > pinboard
INPUT
<DT>Phabricator
<DD>#bug #tracking
<DT>The hidden commands for diagnosing and improving your Netflix streaming quality – Quartz
<DT>Icelandic Farm Holidays | Local experts in Iceland vacations
<DD>#iceland #tour #car #drive #self Self-driving tour of Iceland
OUTPUT:
<DT>Phabricator
<DD>
<DT>The hidden commands for diagnosing and improving your Netflix streaming quality – Quartz
<DT>Icelandic Farm Holidays | Local experts in Iceland vacations
<DD> Self-driving tour of Iceland
I'm trying to filter/append lines of hex data from a large log-file, using Ruby and RegEx.
The lines of the log-file that I need look like this:
Data: 10 55 61 (+ lots more hex data)
I want to add all of the hex data, for further processing later. The regex /^\sData:(.+)/ should do the trick.
My Ruby-program looks like this:
puts "Start"
fileIn = File.read("inputfile.txt")
fileOut = File.new("outputfile.txt", "w+")
fileOut.puts "Start of regex data\n"
fileIn.each_line do
dataLine = fileIn.match(/^\sData:(.+)/).captures
fileOut.write dataLine
end
fileOut.puts "\nEOF"
fileOut.close
puts "End"
It works - sort of - but the lines in the output file are all the same, just repeating the result of the first regex match.
What am I doing wrong?
You are iterating over the same entire file. You need to iterate over the line.
fileIn.each_line do |line|
dataLine = line.match(/^\sData:(.+)/).captures
fileOut.write dataLine
end
I have a big text file that contains - among others- lines like these:
"X" : "452345230"
I want to find all lines that contain "X" , and take just the number (without the quotation marks), and then output the numbers in another file, in this fashion:
452349532
234523452
213412411
219456433
etc.
What I did so far is this:
myfile = File.open("myfile.txt")
x = []
myfile.grep(/"X"/) {|line|
x << line.match( /"(\d{9})/ ).values_at( 1 )[0]
puts x
File.open("output.txt", 'w') {|f| f.write(x) }
}
it works, but the list it produces is of this form:
["23419230", "2349345234" , ... ]
How do I output it like I showed before, just numbers and each number in a line?
Thanks.
Here's a solution that doesn't leave files open:
File.open("output.txt", 'w') do |output|
File.open("myfile.txt").each do |line|
output.puts line[/\d{9}/] if line[/"X"/]
end
end
I couldn't reproduce what you saw:
$ cat myfile.txt
"X" : "452345230"
"X" : "452345231"
"X" : "452345232"
"X" : "452345233"
$ ./scanner.rb
452345230
452345230
452345231
452345230
452345231
452345232
452345230
452345231
452345232
452345233
$ cat output.txt
452345230452345231452345232452345233$
However, I did notice that your application is incredibly wasteful and probably not doing what you expect: You open output.txt, write some content to it, then close it again. The next time it is opened in the loop, it is overwritten. If your file is 1000 lines long, this won't be so bad, you're only making 1000 files. If your file is 1,000,000 lines long, this is going to represent a pretty horrible performance penalty as you create a file, write into it, and then delete it again, one million times. Oops.
I re-wrote your tool a little bit:
$ cat scanner.rb
#!/usr/bin/ruby -w
myfile = File.open("myfile.txt")
output = File.open("output.txt", 'w')
myfile.grep(/"X"/) {|line|
x = line.match( /"(\d{9})/ ).values_at( 1 )[0]
puts x
output.write(x + "\n")
}
This opens each file exactly onces, writes each new line one at a time, and then lets them both be closed when the application quits. Depending upon if this is a small portion of your application or the entire thing, this might be alright. (If this is a small portion of the program, then definitely close the files when you're done with them.)
This might still be wasteful for one million matched lines -- those writes are almost certainly handed straight to the system call write(2), which will involve some overhead.
How many of these will you be running? Millions? Billions? If this needs more refinement feel free to ask...
Solution:
myfile = File.open("myfile.txt")
File.open("output.txt", 'w') do |output|
content = myfile.lines.map { |line| line.scan(/^"X".*(\d{9})/) }.flatten.join("\n")
output.write(content)
end
Edited: I updated the code reducing it a bit. If the example above seems complicated, you can also grab the data you want with the following statement (could be a little bit clear of what's happening):
content = myfile.lines.select { |line| line =~ /"X"/ }.map { |line| line.scan(/\d{9}/) }.join("\n")