I have a string id <- "Hello these are words N12345678 hooray how fun".
I would like to extract just N12345678 from this string.
So far I have used strsplit(id, " "). Now I have
>id
>[[1]]
>[1] "Hello" "these" "are" "words" "N12345678" "hooray" "how"
>[8] "fun"
Which is of type list and of length 1 (despite apparently having 8 elements?)
If I then use id <- id[grep("^[N][0-9]",id)],
id is an empty list.
I think what I need to do is split the string into a list of length 8 with each element as a substring and then grep should be able to pick out the pattern, but I'm not sure how to go about that.
Use regmatches
> regmatches(id, regexpr("N[0-9]+", id))
[1] "N12345678"
If you insist on using strsplit. I think this can solve the problem:
id <- "Hello these are words N12345678 hooray how fun"
id = strsplit(id, " ")
id[[1]][grep("^N[1-9]", id[[1]])]
Notice that I haven't changed your regex. It could be more precise expression such as ^N\\d+$.
Do you know about strtok? It will parse your input line on certain characters. For the purpose of my example, I am breaking off a piece of my string every time I hit a space.
tempVar = strtok(string, " ");
// tempVar has "id" or everything up to the first space
while (tempVar != NULL)
{
tempVar = strtok(NULL, " ");
//now tempVar picked up the next word, and will loop picking up the next word until the end of string
}
Using this, your "Hello these are words N123456789 Hooray" would do this:
tempVar would be Hello, then "these" etc etc.
Each time through the loop tempVar would get a new value. So i would suggest evaluating tempVar in the loop (before grabbing the next one) so that you can stop when you have N123456789
Try:
gsub('\\b[a-zA-Z]+\\b','',id)
Related
This question already has answers here:
Kotlin function for getting start and end index of substring
(2 answers)
Closed 1 year ago.
I want to find index from string. How can i find the index of the first alphabet of second last word in a string.
val index = "Hey! How are you men? How you doing"
i want to search you doing from the above string, but i want y index from the word you. I did some code to find index but I am unable to find it.
fun main(vararg args: String) {
val inputString = "Hey! How are you men? How you doing"
val regex = "you doing".toRegex()
val match = regex.find(inputString)!!
println(match.value)
println(match.range)
}
This regex finds the last two words in your sentence and calculates the index by subtracting the length of the two words from the length of the string.
val result = Regex("^(?:.*?\\s+)?([^\\s]+\\s+[^\\s]+)$").matchEntire(inputString)
if (result != null) {
println(inputString.length - result.groupValues[1].length)
} else {
println("not supported")
}
Supports inputs like
Hey! How are you men? How you doing
Hey! How are you men? How you doing?
Hey! How are you, John?
Hello there!
Split the string, then take the first character of the second-to-last element of the resulting array.
If you are looking for the index of the y in you doing related to the entire string (Hey! How are you men? How you doing), you can use indexOf.
val inputString = "Hey! How are you men? How you doing"
val matchString = "you doing"
val matchIndex = inputString.indexOf(matchString)
More info on indexOf here.
If you don't want to use a regex (which you probably shouldn't unless you need the efficiency) the simplest option is probably what #samuei says:
index.split(' ').takeLast(2).first().first()
(take the last two words, take the first of those, and then the first character of that)
If you want to mess with indices instead you could do this kind of thing:
val lastSpaceIndex = index.lastIndexOf(' ')
val secondToLastSpace = index.lastIndexOf(' ', startIndex = lastSpaceIndex -1)
println(index.get(secondToLastSpace + 1))
where you're finding the index of the last space, then the index of the last space before that one, and then grabbing the character after that. But this is already getting a lot less readable, and is it worth the extra complexity? Your call!
I am using strtok to divide a string in several parts.
In this example, all sections will be read from the string, which are bounded by a colon or a semicolon
char string[] = "Alice1:IscoolAlice2; Alert555678;Bob1:knowsBeepBob2;sees";
char delimiter[] = ":;";
char *p;
p = strtok(string, delimiter);
while(p != NULL) {
cout << "Result: " << p << endl;
p = strtok(NULL, delimiter);
}
As results I get:
Result: Alice1
Result: IscoolAlice2
Result: Alert555678
Result: Bob1
Result: knowsBeepBob2
Result: sees
But I would like to get this results:
Result: Alice1:
Result: Alice2;
Result: Bob1:
Result: Bob2;
The restriction is that I can only choose individual characters when I use strtok.
Does anyone know an alternative for strtok that I also can search for strings?
Or has anyone an idea to solve my problem?
You can not do that task with strtok since you need more complex search
Although I am not sure what is your string as delimiter but the same output can be done with:
char string[] = "Alice1:IscoolAlice2; Alert555678;Bob1:knowsBeepBob2;sees";
char delimiter[] = "(?:Alice|Bob)\\d.";
std::regex regex( delimiter );
std::regex_iterator< const char* > first( std::begin( string ), std::end( string ), regex ), last;
while( first != last ){
std::cout << "Result: " << first->str() << '\n';
++first;
}
the output:
Result: Alice1;
Result: Alice2;
Result: Bob1;
Result: Bob2;
It's just a simple bit of scratch logic, along these lines:
char *ptr = string;
while(*ptr)
{
printf("Result:");
while(*ptr)
{
printf("%c", *ptr);
if(ispunc(*ptr))
{
ptr++;
printf("\n");
break;
}
else
{
ptr++;
}
}
}
It's not possible with your stated data set to properly split it the way you want. You can come up with a "just so" rule to split literally just the data you showed, but given the messy nature of the data it's highly likely it'll fail on other examples. Let's start with this token.
IscoolAlice2
How is a computer program supposed to know which part of this is the name and which is not? You want to get "Alice2" out of this. If you decide that a capital letter specifies a name then it will just spit out the "name" IscoolAlice2. The same with:
knowsBeepBob2
If you search for the first capital letter then the program will decide his name is BeepBob2, so in each case searching for the last occurance of a capital letter in the token finds the name. But what if a name contains two capital letters? The program will cut their name off and you can't do anything about that.
If you're happy to live with these sorts of limitations you can do an initial split via strtok using only the ; character, which gives:
Alice1:IscoolAlice2
Alert555678
Bob1:knowsBeepBob2
sees
Which is less than ideal. You could then specify a rule such that a name exists in any row which contains a : taking anything left of the : as a name, and then finding the last capital letter and anything from that point is also a name. That would give you the output you desire.
But the rules I outlined are extremely specific to the data that was just fed in. If anything about other samples of data deviates at all from this (e.g. a name with two capitals in it) then it will fail as there will be no way on Earth the program could determine where the "name" starts.
The only way to fix this is to go back to where the data is coming from and format it differently so that there is some sort of punctuation before the names.
Or alternatively you need a full database of all possible names that could appear, then search for them, find any characters up to the next : or ; and append them and print the name. But that seems extremely impractical.
I have the following string:
{'output',{'variable','VGRG_Pos_Var1/Parameters/D_foo'},'date',734704.60904050921}
I would like to verify the format of the string that the word 'variable' is the second word and i would like to retrive the string after the last '/' in the 3rd string (In this example 'D_foo').
how could i verify this and retrive the sting i search?
I tried the following:
regexp(str,'{''\w+'',{''variable'',''([(a-z)|(A-Z)|/|_])+')
without success
REMARK
The string to analysis is not splited after the komma, it is only due to length of the string.
EDIT
my string is:
'{''output'',{''variable'',''VGRG_Pos_Var1/Parameters/D_foo''},''date'',734704.60904050921}';
and not a cell, which could be understood. I added the sybol ' at the start and end of the string to symbolizied that it is a string.
I realise that you mention using regexp in the question, but I'm not sure if this is a requirement? If other solutions are acceptable you could try this:
str='{''output'',{''variable'',''VGRG_Pos_Var1/Parameters/D_foo''},''date'',734704.60904050921}';
parts1=textscan( str, '%s','delimiter',{',','{','}'},'MultipleDelimsAsOne',1);
parts2=textscan( parts1{1}{3}, '%s','delimiter',{'/',''''},'MultipleDelimsAsOne',1);
string=parts2{1}{end}
match=strcmp(parts1{1}{2},'variable')
To answer the first part of your question, you can write this:
str = {'output',{'variable','VGRG_Pos_Var1/Parameters/D_foo'},'date',734704.60904050921};
temp = str(2); %this holds the cell containing the two strings
if cmpstr(temp{1}(1), 'variable')
%do stuff
end
For the second part you can do this:
str = {'output',{'variable','VGRG_Pos_Var1/Parameters/D_foo'},'date',734704.60904050921};
temp = str(2); %like before, this contains the cell
temp = temp{1}(2); %this picks out the second string in the cell
temp = char(temp); %turns the item from a cell to a string
res = strsplit(temp, '/'); %splits the string where '/' are found, res is an array of strings
string = res(3); %assuming there will always be just 2 '/'s.
I need to determine whether a string begins with a number - I've tried the following to no avail:
if (matches("^[0-9].*)", upper(text))) str = "Title"""
I'm new to DXL and Regex - what am I doing wrong?
You need the caret character to indicate a match only at the start of a string. I added the plus character to match all the numbers, although you might not need it for your situation. If you're only looking for numbers at the start, and don't care if there is anything following, you don't need anymore.
string str1 = "123abc"
string str2 = "abc123"
string strgx = "^[0-9]+"
Regexp rgx = regexp2(strgx)
if(rgx(str1)) { print str1[match 0] "\n" } else { print "no match\n" }
if(rgx(str2)) { print str2[match 0] "\n" } else { print "no match\n" }
The code block above will print:
123
no match
#mrhobo is correct, you want something like this:
Regexp numReg = "^[0-9]"
if(numReg text) str = "Title"
You don't need upper since you are just looking for numbers. Also matches is more for finding the part of the string that matches the expression. If you just want to check that the string as a whole matches the expression then the code above would be more efficient.
Good luck!
At least from example I found this example should work:
Regexp plural = regexp "^([0-9].*)$"
if plural "15systems" then print "yes"
Resource:
http://www.scenarioplus.org.uk/papers/dxl_regexp/dxl_regexp.htm
I have a file that contains rows and columns of information like:
104857 Big Screen TV 567.95
573823 Blender 45.25
I need to parse this information into three separate items, a string containing the identification number on the left, a string containing the item name, and a double variable containing the price. The information is always found in the same columns, i.e. in the same order.
I am having trouble accomplishing this. Even when not reading from the file and just using a sample string, my attempt just outputs a jumbled mess:
string input = "104857 Big Screen TV 567.95";
string tempone = "";
string temptwo = input.substr(0,1);
tempone += temptwo;
for(int i=1 ; temptwo != " " && i < input.length() ; i++)
{
temptwo = input.substr(j,j);
tempone += temp2;
}
cout << tempone;
I've tried tweaking the above code for quite some time, but no luck, and I can't think of any other way to do it at the moment.
You can find the first space and the last space using std::find_first_of and std::find_last_of . You can use this to better split the string into 3 - first space comes after the first variable and the last space comes before the third variable, everything in between is the second variable.
How about following pseudocode:
string input = "104857 Big Screen TV 567.95";
string[] parsed_output = input.split(" "); // split input string with 'space' as delimiter
// parsed_output[0] = 104857
// parsed_output[1] = Big
// parsed_output[2] = Screen
// parsed_output[3] = TV
// parsed_output[4] = 567.95
int id = stringToInt(parsed_output[0]);
string product = concat(parsed_output[1], parsed_output[2], ... ,parsed_output[length-2]);
double price = stringToDouble(parsed_output[length-1]);
I hope, that's clear.
Well try breaking down the files components:
you know a number always comes first, and we also know a number has no white spaces.
The string following the number CAN have whitespaces, but won't contain any numbers(i would assume)
After this title, you're going to have more numbers(with no whitespaces)
from these components, you can deduce:
grabbing the first number is as simple as reading in using the filestream <<.
getting the string requires you to check until you reach a number, grabbing one character at a time and inserting that into a string. the last number is just like the first, using the filestream <<
This seems like homework so i'll let you put the rest together.
I would try a regular expression, something along these lines:
^([0-9]+)\s+(.+)\s+([0-9]+\.[0-9]+)$
I am not very good at regex syntax, but ([0-9]+) corresponds to a sequence of digits (this is the id), ([0-9]+\.[0-9]+) is the floating point number (price) and (.+) is the string that is separated from the two number by sequences of "space" characters: \s+.
The next step would be to check if you need this to work with prices like ".50" or "10".