word substitution in file

[Xan Xann]

Hi,

Can anyone help me in that?
I just want to write the following function:

substitute(f,g,w,x)

where f and g are files and w and x are strings
That function substitutes all the ocurrences of w in the file f and
writes x to g

For example, if f is:
"
Hello folks or
old men
"

and w = "ol" and x="ur"

then g is:

"
Hello furks or
urd men
"

Can anyone show me some code?
I thinked to pass file to string but I thinked it was not very fast.
Better directly

 

[Xan Xann]

s/File.open(dest)/File.open(dest,"w")/

Also "not tested!". That may seem obvious at this point.

It does not work!!!:
wiki.rb:10: parse error, unexpected kEND

 

[Eero Saynatkari]

#!/usr/bin/ruby

def substitute(source,dest,find,replace)
data = File.read(source)
result = data.gsub(/#{find}/,replace)
File.open(dest,"w") { |f| f.write(result) } if data != result
end

The equality test there is probably unnecessary.
What you could do for a bit lower a cost, if you
really want to avoid the possible write overhead:

# Untested too
require 'fileutils'

def FileUtils.s(source, dest, subs = {})
data = File.read source
search = /#{subs.keys.map {|k| Regexp.escape k}.join '|'}/
result = data.gsub(search) {|found| subs[found]}
File.open(dest, 'w') {|f| f.write result} if $& # Regex matched
end

FileUtils.s 'src.txt', 'dest.txt', 'foo' => 'bar'

 

[Xan Xann]

/ ...


My original code was actually pseudo-code, unbeknownst to me.

------------------------------------------

#!/usr/bin/ruby

def substitute(source,dest,find,replace)
data = File.read(source)
result = data.gsub(/#{find}/,replace)
File.open(dest,"w") { |f| f.write(result) } if data != result
end

substitute("temp.txt","result.txt","i","x")

temp.txt = "This is a test line."

result.txt = "Thxs xs a test lxne."

Tested, which I should have done in the first place.

I get this error:

wiki.rb:7:in `read': can't convert File into String (TypeError)
from wiki.rb:7:in `substitute'
from wiki.rb:12


with code:

require 'fileutils'

f1 = File.open("original.txt")
f2 = File.open("canviada.txt")

def substitute(source,dest,find,replace)
data = File.read(source)
result = data.gsub(/#{find}/,replace)
File.open(dest,"w") { |f| f.write(result) } if data != result
end

substitute(f1,f2,"ol","ur")


What happens?
Thanks,
Xan.

 

[Xan Xann]

#!/usr/bin/ruby

def substitute(source,dest,find,replace)
data = File.read(source)
result = data.gsub(/#{find}/,replace)
File.open(dest,"w") { |f| f.write(result) } if data != result
end

The equality test there is probably unnecessary.
What you could do for a bit lower a cost, if you
really want to avoid the possible write overhead:

# Untested too
require 'fileutils'

def FileUtils.s(source, dest, subs = {})
data = File.read source
search = /#{subs.keys.map {|k| Regexp.escape k}.join '|'}/
result = data.gsub(search) {|found| subs[found]}
File.open(dest, 'w') {|f| f.write result} if $& # Regex matched
end

FileUtils.s 'src.txt', 'dest.txt', 'foo' => 'bar'

This WORKS!!!! finally


Thank you very much
It seems it supports regexp expressions. Is it true?

Xan.

 

[Eero Saynatkari]

# Untested too
require 'fileutils'

def FileUtils.s(source, dest, subs = {})
data = File.read source
search = /#{subs.keys.map {|k| Regexp.escape k}.join '|'}/
result = data.gsub(search) {|found| subs[found]}
File.open(dest, 'w') {|f| f.write result} if $& # Regex matched
end

FileUtils.s 'src.txt', 'dest.txt', 'foo' => 'bar'

This WORKS!!!! finally


Thank you very much
It seems it supports regexp expressions. Is it true?

It just substitutes strings with their counterparts
given as the Hash. Regular expression support would
be a bit more involved.

 

[Xan Xann]

# Untested too
require 'fileutils'

def FileUtils.s(source, dest, subs = {})
data = File.read source
search = /#{subs.keys.map {|k| Regexp.escape k}.join '|'}/
result = data.gsub(search) {|found| subs[found]}
File.open(dest, 'w') {|f| f.write result} if $& # Regex matched
end

FileUtils.s 'src.txt', 'dest.txt', 'foo' => 'bar'

This WORKS!!!! finally


Thank you very much
It seems it supports regexp expressions. Is it true?

It just substitutes strings with their counterparts
given as the Hash. Regular expression support would
be a bit more involved.

Well, thanks you very much for your help

Xan.

 

[Xan Xann]

Xan Xann wrote:

/ ...


Here is my example call to 'substitute':

substitute("temp.txt","result.txt","i","x")

You can see that I use strings containing the names of the files.

Here is your example call to 'substitute':

f1 = File.open("original.txt")
f2 = File.open("canviada.txt")

substitute(f1,f2,"ol","ur")

You are using open file handles instead of strings. The remedy is,
instead
of using your example of my example, use my example.

Yes, sorry. What stupid error!!!

Thanks,
Xan.