I am comparing strings from a text file, but for some reason they never match. If I do it in ruby it is very easy, but in processing I can not get it to work.
this is the ruby code that works:
f=File.open("priceMap_current_new.txt")
f.each do |str|
arrstr=str.split(";")
if arrstr.length==1
puts arrstr[0].inspect if arrstr[0]=="next\n"
end
end
Now here's the processing version that doesn't work, actually it doesnt even work without reading from file:
String[] mystr={"number;zero","number;one","number;two","number;three","number;four"};
for(int i=0;i<mystr.length;i++){
String[] numbers=split(mystr[i],";");
if(numbers[0]=="number"){
println("shoooooooooooooooooout");
}
}
Additionally I would like to ask if there's a way to inspect elements like in ruby, its very handy, because if I print pts[0] in processing I get "next" when its actually "next\n"
or also how to check datatypes in processing. Thanks!
Use if (numbers[0].equals("number"))
From: Processing doco
To compare the contents of two Strings, use the equals() method, as in
"if (a.equals(b))", instead of "if (a == b)".
Related
I want to use printing command bellow in many places of my script. But I need to keep replacing "Survived" with some other string.
print(df.Survived.value_counts())
Can I automate the process by formating variable the same way as string? So if I want to replace "Survived" with "different" can I use something like:
var = 'different'
text = 'df.{}.value_counts()'.format(var)
print(text)
unfortunately this prints out "df.different.value_counts()" as as a string, while I need to print the value of df.different.value_counts()
I'm pretty sure alot of IDEs, have this option that is called refactoring, and it allows you to change a similar line of code/string on every line of code to what you need it to be.
I'm aware of VSCode's way of refactoring, is by selecting a part of the code and right click to select the option called change all occurances. This will replace the exact code on every line if it exists.
But if you want to do what you proposed, then eval('df.{}.value_counts()'.format(var)) is an option, but this is very unsecured and dangerous, so a more safer approach would be importing the ast module and using it's literal_eval function which is safer. ast.literal_eval('df.{}.value_counts()'.format(var)).
if ast.literal_eval() doesn't work then try this final solution that works.
def cat():
return 1
text = locals()['df.{}.value_counts'.format(var)]()
Found the way: print(df[var].value_counts())
First and foremost, I'm not familiar with Perl at all. I've been studying C++ primarily for the last 1/2 year. I'm in a class now that that is teaching Linux commands, and we have short little topics on languages used in Linux, including Perl, which is totally throwing me for a loop (no pun intended). I have a text file that contains a bunch of random numbers separated by spaces and tabs, maybe even newlines, that gets read into the program via a filehandle. I'm supposed to write 2 lines of code that split the lines of numbers and merge them into one array, inside of a foreach loop. I'm not looking for an answer, just a nudge in the right direction. I've been trying different things for multiple hours and feel totally silly I can't get it, I'm totally lost with the syntax. Its just a bit odd not working inside a compiler and out of my comfort zone working outside of C++. I really appreciate it. I've included a few photos. Basically, the code we are writing it just to store the numbers and the rest of the program will determine the smallest number and sum of all numbers. Mine is currently incorrect because I'm not sure what to do. In the output photo, it will display all the numbers being entered in via the text file, so you can see them.
Several things to fix here. First of all, please don't post screenshots of your sample data or code, as it makes it impossible to copy and paste to test your code or data. Post your code/data by indenting it with four spaces and a newline preceding the code block.
Add use strict; in your script. This should be lesson 0 in your class. After that add my to all variable declarations.
To populate #all_numbers with contents of each line's numbers, without using push, you can use something like this:
foreach my $line (#output_lines)
{
my #numbers = split /\s/, $line;
#all_numbers = (#all_numbers, #numbers);
}
You say you're "not looking for an answer," so here's your nudge:
You're almost there. You split each line well (using split/\s/) and store the numeric values in #all_numbers. However, notice that each time around in the loop, you replace (using the assignment, #all_numbers = ...) the whole contents of #all_numbers with the numbers you found in the current line. Effectively, you're throwing away everything you've stored from the previous lines.
Instead, you want to add to #all_numbers, not replace #all_numbers. Have a look at the push() function for how to do this.
NB: Your split() call is fine, but it's more customary to use split(' ', $line) in this case. (See split(): you can use a single space, ' ', instead of the pattern, /\s/, when you want to split on any whitespace.)
I hope you need to store the all splitting element into array, so you looking for push function.
foreach $line (#input_lines)
{
push(#all_numbers,split(/\s/,$line));
}
Your problem is, in every iteration, the splitted value is over written in an array not to append together. For example,
#array = qw(one two three);
#array = qw(five four seven);
print "#array";
output is five four seven not the one two three five four seven because this is reinitialize with a new values. You want to append the new values in the array in before or after use unshift or push
for example
#array = qw(one two three);
push(#array,qw(five four seven));
Another way:
my #all_numbers = map { split ' ', $_ } #output_lines;
See http://perldoc.perl.org/functions/map.html
i´ve got small problem and before I spend even more time in trying to solve it i´d like to know if what I want to do is even possible ( and maybe input on how to do it^^).
My problem:
I want to take some text and then split it into different strings at every whitespace (for example "Hello my name is whatever" into "Hello" "my" "name" "is" "whatever").
Then I want to set every string with it´s own variable so that I get something alike to a= "Hello" b= "my" and so on. Then I want to compare the strings with other strings (the idea is to get addresses from applications without having to search through them so I thought I could copy a telephone book to define names and so on) and set matching input to variables like Firstname , LastName and street.
Then, and here comes the "I´d like to know if it´s possible" part I want it to put it into our database, this means I want it to copy the string into a text field and then to go to the next field via tab. I´ve done something like this before with AutoIT but i´ve got no idea how to tell AutoIT whats inside the strings so I guess it must be done through the programm itself.
I´ve got a little bit of experience with c++, python and BATCH files so it would be nice if anyone could tell me if this can even be done using those languages (and I fear C++ can do it and I´m just to stupid to do so).
Thanks in advance.
Splitting a string is very simple, there is usually a built in method called .split() which will help you, the method varies from language to language.
When you've done a split, it will be assigned to an array, you can then use an index to get the variables, for example you'd have:
var str = "Hello, my name is Bob";
var split = str.split(" ");
print split[0]; // is "Hello,"
print split[1]; // is "my" etc
You can also use JSON to return data so you could have an output like
print split["LastName"];
What you're asking for is defiantly possible.
Some links that could be useful:
Split a string in C++?
https://code.google.com/p/cpp-json/
I have seen a lot of C/C++ based solutions to this problem where we have to write a program that upon execution prints its own source.
some solutions --
http://www.cprogramming.com/challenges/solutions/self_print.html
Quine Page solution in many languages
There are many more solutions on the net, each different from the other. I wonder how do we approach to such a problem, what goes inside the mind of the one who solves it. Lend me some insights into this problem... While solutions in interpreted languages like perl, php, ruby, etc might be easy... i would like to know how does one go about designing it in compiled languages...
Aside from cheating¹ there is no difference between compiled and interpreted languages.
The generic approach to quines is quite easy. First, whatever the program looks like, at some point it has to print something:
print ...
However, what should it print? Itself. So it needs to print the "print" command:
print "print ..."
What should it print next? Well, in the mean time the program grew, so it needs to print the string starting with "print", too:
print "print \"print ...\""
Now the program grew again, so there's again more to print:
print "print \"print \\\"...\\\"\""
And so on.
With every added code there's more code to print.
This approach is getting nowhere,
but it reveals an interesting pattern:
The string "print \"" is repeated over and over again.
It would be nice to put the repeating part
into a variable:
a = "print \""
print a
However, the program just changed,
so we need to adjust a:
a = "a = ...\nprint a"
print a
When we now try to fill in the "...",
we run into the same problems as before.
Ultimately, we want to write something like this:
a = "a = " + (quoted contents of a) + "\nprint a"
print a
But that is not possible,
because even if we had such a function quoted() for quoting,
there's still the problem that we define a in terms of itself:
a = "a = " + quoted(a) + "\nprint a"
print a
So the only thing we can do is putting a place holder into a:
a = "a = #\nprint a"
print a
And that's the whole trick!
Anything else is now clear.
Simply replace the place holder
with the quoted contents of a:
a = "a = #\nprint a"
print a.replace("#", quoted(a))
Since we have changed the code,
we need to adjust the string:
a = "a = #\nprint a.replace(\"#\", quoted(a))"
print a.replace("#", quoted(a))
And that's it!
All quines in all languages work that way
(except the cheating ones).
Well, you should ensure that you replace only
the first occurence of the place holder.
And if you use a second place holder,
you can avoid needing to quote the string.
But those are minor issues
and easy to solve.
If fact, the realization of quoted() and replace()
are the only details in which the various quines really differ.
¹ by making the program read its source file
There are a couple of different strategies to writing quines. The obvious one is to just write code that opens the code and prints it out. But the more interesting ones involve language features that allow for self-embedding, like the %s-style printf feature in many languages. You have to figure out how to embed something so that it ends up resolving to the request to be embedded. I suspect, like palindromes, a lot of trial and error is involved.
The usual approach (when you can't cheat*) is to write something that encodes its source in a string constant, then prints out that constant twice: Once as a string literal, and once as code. That gets around the "every time I write a line of code, I have to write another to print it out!" problem.
'Cheating' includes:
- Using an interpreted language and simply loading the source and printing it
- 0-byte long files, which are valid in some languages, such as C.
For fun, I came up with one in Scheme, which I was pretty proud of for about 5 minutes until I discovered has been discovered before. Anyways, there's a slight modification to the "rules" of the game to better count for the duality of data and code in Lisp: instead of printing out the source of the program, it's an S-expression that returns itself:
((lambda (x) (list x `',x)) '(lambda (x) (list x `',x)))
The one on Wikipedia has the same concept, but with a slightly different (more verbose) mechanism for quoting. I like mine better though.
One idea to think about encoding and how to give something a double meaning so that it can be used to output something in a couple of forms. There is also the cavaet that this type of problem comes with restrictions to make it harder as without any rules other than the program output itself, the empty program is a solution.
How about actually reading and printing your source code? Its not difficult at all!! Heres one in php:
<?php
{
header("Content-Type: text/plain");
$f=fopen("5.php","r");
while(!feof($f))
{
echo fgetc($f);
}
fclose($f);
}
?>
In python, you can write:
s='c=chr(39);print"s="+c+s+c+";"+s';c=chr(39);print"s="+c+s+c+";"+s
inspired from this self printing pseudo-code:
Print the following line twice, the second time with quotes.
"Print the following line twice, the second time with quotes."
I've done a AS3 example for those interested in this
var program = "var program = #; function main(){trace(program.replace('#',
String.fromCharCode(34) + program + String.fromCharCode(34)))} main()";
function main(){
trace(program.replace('#', String.fromCharCode(34) + program + String.fromCharCode(34)))
}
main()
In bash it is really easy
touch test; chmod oug+x test; ./test
Empty file, Empty output
In ruby:
puts File.read(_ _ FILE _ _)
I'm using the following groovy code to search a file for a string, an account number. The file I'm reading is about 30MB and contains 80,000-120,000 lines. Is there a more efficient way to find a record in a file that contains the given AcctNum? I'm a novice, so I don't know which area to investigate, the toList() or the for-loop. Thanks!
AcctNum = 1234567890
if (testfile.exists())
{
lines = testfile.readLines()
words = lines.toList()
for (word in words)
{
if (word.contains(AcctNum)) { done = true; match = 'YES' ; break }
chunks += 1
if (done) { break }
}
}
Sad to say, I don't even have Groovy installed on my current laptop - but I wouldn't expect you to have to call toList() at all. I'd also hope you could express the condition in a closure, but I'll have to refer to Groovy in Action to check...
Having said that, do you really need it split into lines? Could you just read the whole thing using getText() and then just use a single call to contains()?
EDIT: Okay, if you need to find the actual line containing the record, you do need to call readLines() but I don't think you need to call toList() afterwards. You should be able to just use:
for (line in lines)
{
if (line.contains(AcctNum))
{
// Grab the results you need here
break;
}
}
When you say efficient you usually have to decide which direction you mean: whether it should run quickly, or use as few resources (memory, ...) as possible. Often both lie on opposite sites and you have to pick a trade-off.
If you want to search memory-friendly I'd suggest reading the file line-by-line instead of reading it at once which I suspect it does (I would be wrong there, but in other languages something like readLines reads the whole file into an array of strings).
If you want it to run quickly I'd suggest, as already mentioned, reading in the whole file at once and looking for the given pattern. Instead of just checking with contains you could use indexOf to get the position and then read the record as needed from that position.
I should have explained it better, if I find a record with the AcctNum, I extract out other information on the record...so I thought I needed to split the file into multiple lines.
if you control the format of the file you are reading, the solution is to add in an index.
In fact, this is how databases are able to locate records so quickly.
But for 30MB of data, i think a modern computer with a decent harddrive should do the trick, instead of over complicating the program.