Friends:
I have to process a CSV file, using Perl language and produce an Excel as output, using the Excel::Writer::XSLX module. This is not a homework but a real life problem, where I cannot download whichever Perl version (actually, I need to use Perl 5.6), or whichever Perl module (I have a limited set of them). My OS is UNIX. I can also use (embedding in Perl) ksh and csh (with some limitation, as I have found so far). Please, limit your answers to the tools I have available. Thanks in advance!
Even though I am not a Perl developer, but coming from other languages, I have already done my work. However, the customer is asking for extra processing where I am getting stuck on.
1) The stones in the road I found are coming from two sides: from Perl and from Excel particular styles of processing data. I already found a workaround to handle the Excel, but -as mentioned in the subject- I have difficulties while processing zeroes found in CSV input file. To handle the Excel, I am using the '0 way which is the final way for data representation that Excel seems to have while using the # formatting style.
2) Scenario:
I need to catch standalone zeroes which might be present in whichever line / column / cell of the CSV input file and put them as such (as zeroes) in the Excel output file.
I will go directly to the point of my question to avoid loosing your valuable time. I am providing more details after my question:
Research and question:
I tried to use Perl regex to find standalone "0" and replace them by whichever string, planning to replace them back to "0" at the end of processing.
perl -p -i -e 's/\b0\b/string/g' myfile.csv`
and
perl -i -ple 's/\b0\b/string/g' myfile.csv
Are working; but only from command line. They aren't working when I call them from the Perl script as follows:
system("perl -i -ple 's/\b0\b/string/g' myfile.csv")
Do not know why... I have already tried using exec and eval, instead of system, with the same results.
Note that I have a ton of regex that work perfectly with the same structure, such as the following:
system("perl -i -ple 's/input/output/g' myfile.csv")
I have also tried using backticks and qx//, without success. Note that qx// and backticks have not the same behavior, since qx// is complaining about the boundaries \b because of the forward slash.
I have tried using sed -i, but my System is rejecting -i as invalid flag (do not know if this happens in all UNIX, but at least happens in the one at work. However is accepting perl -i).
I have tried embedding awk (which is working from command line), in this way:
system `awk -F ',' -v OFS=',' '$1 == \"0\" { $1 = "string" }1' myfile.csv > myfile_copy.csv
But this works only for the first column (in command line) and, other than having the disadvantage of having extra copy file, Perl is complaining for > redirection, assuming it as "greater than"...
system(q#awk 'BEGIN{FS=OFS=",";split("1 2 3 4 5",A," ") } { for(i in A)sub(0,"string",$A[i] ) }1' myfile.csv#);
This awk is working from command line, but only 5 columns. But not in Perl using #.
All the combinations of exec and eval have also been tested without success.
I have also tried passing to system each one of the awk components, as arguments, separated by commas, but did not find any valid way to pass the redirector (>), since Perl is rejecting it because of the mentioned reason.
Using another approach, I noticed that the "standalone zeroes" seem to be "swallowed" by the Text::CSV module, thus, I get rid off it, and turned back to a traditional looping in csv line by line and a spliter for commas, preserving the zeroes in that way. However I found the "mystery" of isdual in Perl, and because of the limitation of modules I have, I cannot use the Dumper. Then, I also explored the guts of binaries in Perl and tried the $x ^ $x, which was deprecated since version 5.22 but valid till that version (I said mine is 5.6). This is useful to catch numbers vs strings. However, while if( $x ^ $x ) returns TRUE for strings, if( !( $x ^ $x ) ) does not returns TRUE when $x = 0. [UPDATE: I tried this in a devoted Perl script, just for this purpose, and it is working. I believe that my probable wrong conclusion ("not returning TRUE") was obtained when I did not still realize that Text::CSV was swallowing my zeroes. Doing new tests...].
I will appreciate very much your help!
MORE DETAILS ON MY REQUIREMENTS:
1) This is a dynamic report coming from a database which is handover to me and I pickup programmatically from a folder. Dynamic means that it might have whichever amount of tables, whichever amount of columns in each table, whichever names as column headers, whichever amount of rows in each table.
2) I do not know, and cannot know, the column names, because they vary from report to report. So, I cannot be guided by column names.
A sample input:
Alfa,Alfa1,Beta,Gamma,Delta,Delta1,Epsilon,Dseta,Heta,Zeta,Iota,Kappa
0,J5,alfa,0,111.33,124.45,0,0,456.85,234.56,798.43,330000.00
M1,0,X888,ZZ,222.44,111.33,12.24,45.67,0,234.56,0,975.33
3) Input Explanation
a) This is an example of a random report with 12 columns and 3 rows. Fist row is header.
b) I call "standalone zeroes" those "clean" zeroes which are coming in the CSV file, from second row onwards, between commas, like 0, (if the case is the first position in the row) or like ,0, in subsequent positions.
c) In the second row of the example you can read, from the beginning of the row: 0,J5,alfa,0, which in this particular case, are "words" or "strings". In this case, 4 names (note that two of them are zeroes, which required to be treated as strings). Thus, we have a 4 names-columns example (Alfa,Alfa1,Beta,Gamma are headers for those columns, but only in this scenario). From that point onwards, in the second row, you can see floating point (*.00) numbers and, among them, you can see 2 zeroes, which are numbers. Finally, in the third line, you can read M1,0,X888,Z, which are the names for the first 4 columns. Note, please, that the 4th column in the second row has 0 as name, while the 4th column in the third row has ZZ as name.
Summary: as a general picture, I have a table-report divided in 2 parts, from left to right: 4 columns for names, and 8 columns for numbers.
Always the first M columns are names and the last N columns are numbers.
- It is unknown which number is M: which amount of columns devoted for words / strings I will receive.
- It is unknown which number is N: which amount of columns devoted for numbers I will receive.
- It is KNOWN that, after the M amount of columns ends, always starts N, and this is constant for all the rows.
I have done a quick research on Perl boundaries for regex ( \b ), and I have not found any relevant information regarding if it applies or not in Perl 5.6.
However, since you are using and old Perl version, try the traditional UNIX / Linux style (I mean, what Perl inherits from Shell), like this:
system("perl -i -ple 's/^0/string/g' myfile.csv");
The previous regex should do the work doing the change at the start of the each line in your CSV file, if matches.
Or, maybe better (if you have those "standalone" zeroes, and want avoid any unwanted change in some "leading zeroes" string):
system("perl -i -ple 's/^0,/string,/g' myfile.csv");
[Note that I have added the comma, after the zero; and, of course, after the string].
Note that the first regex should work; the second one is just a "caveat", to be cautious.
I have a lot of relatively small files with about 350.000 lines of text.
For example:
File 1:
asdf
wetwert
ddghr
vbnd
...
sdfre
File 2:
erye
yren
asdf
jkdt
...
uory
As you can see line 3 of file 2 is a duplicate of line 1 in file 1.
I want a program / Notepad++ Plugin that can check and remove these duplicates in multiple files.
The next problem I have is that I want all lists to be combined into large 1.000.000 line files.
So, for example, I have these files:
648563 lines
375924 lines
487036 lines
I want them to result in these files:
1.000.000 lines
511.523 lines
And the last 2 files must consist of only unique lines.
How can I possibly do this? Can I use some programs for this? Or a combination of multiple Notepad++ Plugins?
I know GSplit can split files of 1.536.243 into files of 1.000.000 and 536.243 lines, but that is not enough, and it doesn't remove duplicates.
I do want to create my own Notepad++ plugin or program if needed, but I have no idea how and where to start.
Thanks in advance.
You have asked about Notepad++ and are thus using Windows. On the other hand, you said you want to create a program if needed, so I guess the main goal is to get the job done.
This answer uses Unix tools - on Windows, you can get those with Cygwin.
To run the commands, you have to type (or paste) them in the terminal / console.
cat file1 file2 file3 | sort -u | split -l1000000 - outfile_
cat reads the files and echoes them; normally, to the screen, but the pipe | gets the output of the command left to it and pipes it through to the command on the right.
sort obviously sorts them, and the switch -u tells it to remove duplicate lines.
The output is then piped to split which is being told to split after 1000000 lines by the switch -l1000000. The - (with spaces around) tells it to read its input not from a file but from "standard input"; the output in sort -u in this case. The last word, outfile_, can be changed by you, if you want.
Written like it is, this will result in files like outfile_aa, outfile_ab and so on - you can modify this with the last word in this command.
If you have all the files in on directory, and nothing else is in there, you can use * instead of listing all the files:
cat * | sort -u | split -l1000000 - outfile_
If the files might contain empty lines, you might want to remove them. Otherwise, they'll be sorted to the top and your first file will not have the full 1.000.000 values:
cat file1 file2 file3 | grep -v '^\s*$' | sort -u | split -l1000000 - outfile_
This will also remove lines that consist only of whitespace.
grep filters input using regular expressions. -v inverts the filter; normally, grep keeps only lines that match. Now, it keeps only lines that don't match. ^\s*$ matches all lines that consist of nothing else than 0 or more characters of whitespace (like spaces or tabs).
If you need to do this regularly, you can write a script so you don't have to remember the details:
#!/bin/sh
cat * | sort -u | split -l1000000 - outfile_
Save this as a file (for example combine.sh) and run it with
./combine.sh
I have a huge amount of files (in the hundreds of thousands) that all have the same format of name.
The filename format is:
[prefix][number]suffix]
where the [prefix] and [suffix] of all the files is the same, and just the number part changes. The number part is something like 0004732
So the filenames are:
[prefix]004732[suffix]
[prefix]004733[suffix]
[prefix]004734[suffix]
etc.
I need to move a range of about 100,000 files (with consecutive numbers) to another directory, and I was wondering if it is possible to do this with a regular expression.
You're looking for character classes. It's a bit difficult to specify number ranges using regex because it works on text, not numbers, but it can be done something like this (for files 1-100):
prefix[0-1][0-9][0-9]suffix
prefix[0-1]\d\dsuffix #this also works in PERL regex
More complicated numbers get trickier. For 0-211:
prefix([0-1][0-9][0-9]|20[0-9]|21[0-1])suffix
If you're on Windows, install Cygwin, and do the following. If you're on Mac OS X or Linux, just open a terminal. You'll need to do the following:
ls PREFIX* | sed 's/PREFIX\(0[0-9]\)SUFFIX/mv & tmp\/PREFIX\1SUFFIX/' | sh
What is this doing?
Lists all files starting with the specified prefix
Pipes this list to sed, which uses a regex pattern to match only files that fall within the range you specify
Create a new string using the move command
Pipes the move command string to the shell (sh) and executes it
You can tweak the regex to match your number range by looking at the following:
http://www.regular-expressions.info/numericranges.html
To the best of my knowledge, there is no regex (to handle complex cases), but you can use loop easily:
The following code runs in linux. I ran simnilar code on Windows using CygWin and it works as well. Maybe there is similar way to do in Windows.
If the two numbers are with the same digits;
Example: from
[prefix]000012345[suffix]
to
[prefix]000056789[suffix]
:
for (( i=12345; i<56789; i++)); do mv "[prefix]0000$i[suffix]" /newDirectoryPath done
Otherwise you can do with multiple (usually two or three) commands;
Example: from
[prefix]000012345[suffix]
to
[prefix]003456789[suffix]
:
for (( i=12345; i<99999; i++)); do mv "[prefix]0000$i[suffix]" /newDirectoryPath done
for (( i=100000; i<999999; i++)); do mv "[prefix]000$i[suffix]" /newDirectoryPath done
for (( i=1000000; i<3456789; i++)); do mv "[prefix]00$i[suffix]" /newDirectoryPath done
I am trying to compare two files of strings and remove everything that is in file 1 from file 2 if its there and save it in a third output file. I was going to write a c++ program for this but best i could come up with was O(N^2), is there any commands in Linux to do this? if not what is the most efficient way to do it with c++ ? these files have up to 1 billion strings in one and 10 million in another so O(N^2) is extremely inefficient
ex f1
hello
josh
cory
sam
don
f2
jack
josh
joey
sam
neda
etc
outputfile:
jack
joey
neda
etc
to be clear I am NOT trying to merge them then remove duplicates, i only want duplicates of strings in file 1 removed from file 2.
thanks
fgrep is handy for this: it will grep one file for a set of fixed strings.
fgrep -f f1 -v f2 will print out all lines in f2 that are not found in f1.
You can solve this task by using the Aho-Corasick string matching algorithm. It is used for multiple-keyword search across text and it's time complexity is linear.
There are some C++ implementations of this algorithm on the net. For example this.
In addition, there is a nice-looking python library for this.
However, I'm not sure if the memory complexity is OK when using those sources/libraries. You may have to read the input from the first file in chunks (as it may have billions of characters).
You could code a C++ (or Ocaml) program which reads all the words of the first file and store them in a set of strings (using std::set<std::string> in C++, or module SS = Set.Make(String);; in Ocaml). Filling that set should be O(n log n) complexity (where n is the number of words, i.e. the cardinal of the set). Testing that a file of m words each word belongs (or not) to that set is O (m log n)
Sets are implemented as balanced trees with a logarithmic membership test time.
However, you should probably have used some data base systems to store (and fill) the data. (e.g. PostGreSQL, MariaDB, MongoDB, CouchDB, ....)
I regularly deal with files that look like this (for compatibility with R):
# comments
# more comments
col1 col2 col3
1 a hi
2 b there
. . .
Very often, I will want to read col2 into a vector or other container. It's not hard to write a function that parses this kind of file, but I would be surprised if there were no well tested library to do it for me. Does such a library exist? (As I say, it's not hard to roll your own, but as I am not a C++ expert, it would be some trouble for me to do use the templates that would allow me to use an arbitrary container to contain arbitrary data types.)
EDIT:
I know the name of the column I want, but not what order the columns in this particular file will be in. Columns are separated by an unknown amount white space which may be tabs or spaces (probably not both). The first entry on each line may or may not be preceded by white space, sometimes that will change within one file, e.g.
number letter
8 g
9 h
10 i
Boost split may do what you want, providing you can consistently split on whitespace.
I am not aware of any C++ library that will do this. A simple solution, however, would be to use linux cut. You would have to remove the comments first, which is easily done with sed:
sed -e '/^#/d' <your_file>
Then you could apply the following command which would select just the text from the third column:
cut -d' ' -f3 <your_file>
You could combine those together with a pipe to make it a single command:
sed -e '/^#/d' <your_file> | cut -d' ' -f3 <your_file>
You could run this command programmatically, then rather simply append each line to a stl container.
// pseudocode
while(file.hasNextLine())
{
container << file.readNextLine();
}
For how to actually run cut from within code, see this answer.