The other answers for similar question works if the string is str1 = 'MynameisJohn' within single quotes. For example, str1(1:2) gives 'My'.
But if the string is str1 = "MynameisJohn" with double quotes, the above usage str1(1:2) does not work and gives an out of bounds error. The size of str1 in this case is just a 1 by 1 matrix.
In the second case, how do I split the string to get the words in it, assuming there are no whitespaces (hence delimiters can't be used). We can assume the lenghts of my split are constant.
EDIT
I think I found the answer myself. str2 = char(str1) converts the string array str1 to a character array and then similar constructs str2(1:2) works.
Conversion to char and then indexing works as you have posted. If you would like the result to stay as a string another way to extract substring is to use extract functions. For example,
str1 = string('MynameisJohn');
substr = extractBefore(str1,3)
substr =
string
"My"
In this case substr is still a string type. Doc for extractBefore is at https://www.mathworks.com/help/matlab/ref/extractbefore.html
Related
I have a bunch of users in a list called UserList.
And I do not want the output to have the square brackets, so I run this line:
UserList = [1,2,3,4...]
UserListNoBrackets = str(UserList).strip('[]')
But if I run:
len(UserList) #prints22 (which is correct).
However:
len(UserListNoBrackets) #prints 170 (whaaat?!)
Anyway, the output is actually correct (I'm pretty sure). Just wondering why that happens.
Here:
UserListNoBrackets = str(UserList).strip('[]')
UserListNoBrackets is a string. A string is a sequence of characters, and len(str) returns the numbers of characters in the string. A comma is a character, a white space is a character, and the string represention of an integer has has many characters as there are digits in the integer. So obviously, the length of your UserListNoBrackets string is much greater than the length of you UserList list.
You probably need str.join
Ex:
user_list = [1,2,3,4...]
print(",".join(map(str, user_list)))
Note:
Using map method to convert all int elements in list to string.
Any idea how i can separate a string with character and numbers, for example
12345ABC678 to make it look like this
1|2|3|4|5|A|B|C|6|7|8??
Or if this is not possile, how can i take this string a put every character or nr of it in a different textBox like this?
You can use String.Join and String.ToCharArray:
string input = "12345ABC678";
string result = String.Join("|", input.ToCharArray());
Instead of ToCharArray(creates a new array) you could also cast the string to IEnumerable<char> to force it to use the right overload of String.Join:
string result = String.Join("|", (IEnumerable<char>)input);
use
String aString = "AaBbCcDd";
var chars = aString.ToCharArray();
Then you can loop over the array (chars)
I wanted to know how to remove first character of a string in octave. I am manipulating the string in a loop and after every loop, I want to remove the first character of the remaining string.
Thanks in advance.
If it's just a one-line string then:
short_string = long_string(2:end)
But if you have a cell array of strings then either do it as above if you have a loop already, otherwise you can use this shorthand to do it in one line:
short_strings = cellfun(#(x)(x(2:end)), long_strings, 'uni', false)
Or else if you have a matrix of strings (i.e. all the same length), then you can vectorize it as:
short_strings = long_strings(:, 2:end)
When comparing string to another string using compareTO() method, here we compare one string to another string right. My doubt is which one is argument string in this two
example : int result = str1.compareTo( str2 );
If you write
str1.compareTo(str2)
then you get back an integer that is
negative if str1 precedes str2,
zero if str1 equals str2, and
positive if str1 is comes after str2.
Here, str1 is the receiver object (since it comes before the dot) and str2 is the argument.
I've a question about Fortran 77 and I've not been able to find a solution.
I'm trying to store an array of strings defined as the following:
character matname(255)*255
Which is an array of 255 strings of length 255.
Later I read the list of names from a file and I set the content of the array like this:
matname(matcount) = mname
EDIT: Actually mname value is hardcoded as mname = 'AIR' of type character*255, it is a parameter of a function matadd() which executes the previous line. But this is only for testing, in the future it will be read from a file.
Later on I want to print it with:
write(*,*) matname(matidx)
But it seems to print all the 255 characters, it prints the string I assigned and a lot of garbage.
So that is my question, how can I know the length of the string stored?
Should I have another array with all the lengths?
And how can I know the length of the string read?
Thanks.
You can use this function to get the length (without blank tail)
integer function strlen(st)
integer i
character st*(*)
i = len(st)
do while (st(i:i) .eq. ' ')
i = i - 1
enddo
strlen = i
return
end
Got from here: http://www.ibiblio.org/pub/languages/fortran/ch2-13.html
PS: When you say: matname(matidx) it gets the whole string(256) chars... so that is your string plus blanks or garbage
The function Timotei posted will give you the length of the string as long as the part of the string you are interested in only contains spaces, which, if you are assigning the values in the program should be true as FORTRAN is supposed to initialize the variables to be empty and for characters that means a space.
However, if you are reading in from a file you might pick up other control characters at the end of the lines (particularly carriage return and/or line feed characters, \r and/or \n depending on your OS). You should also toss those out in the function to get the correct string length. Otherwise you could get some funny print statements as those characters are printed as well.
Here is my version of the function that checks for alternate white space characters at the end besides spaces.
function strlen(st)
integer i,strlen
character st*(*)
i = len(st)
do while ((st(i:i).eq.' ').or.(st(i:i).eq.'\r').or.
+ (st(i:i).eq.'\n').or.(st(i:i).eq.'\t'))
i = i - 1
enddo
strlen = i
return
end
If there are other characters in the "garbage" section this still won't work completely.
Assuming that it does work for your data, however, you can then change your write statement to look like this:
write(*,*) matname(matidx)(1:strlen(matname(matidx)))
and it will print out just the actual string.
As to whether or not you should use another array to hold the lengths of the string, that is up to you. the strlen() function is O(n) whereas looking up the length in a table is O(1). If you find yourself computing the lengths of these static strings often, it may improve performance to compute the length once when they are read in, store them in an array and look them up if you need them. However, if you don't notice the slowdown, I wouldn't worry about it.
Depending on the compiler that you are using, you may be able to use the trim() intrinsic function to remove any leading/trailing spaces from a string, then process it as you normally would, i.e.
character(len=25) :: my_string
my_string = 'AIR'
write (*,*) ':', trim(my_string), ':'
should print :AIR:.
Edit:
Better yet, it looks like there is a len_trim() function that returns the length of a string after it has been trimmed.
intel and Compaq Visual Fortran have the intrinsic function LEN_TRIM(STRING) which returns the length without trailing blanks or spaces.
If you want to suppress leading blanks or spaces, use "Adjust Left" i.e. ADJUSTF(STRING)
In these FORTRANs I also note a useful feature: If you pass a string in to a function or subroutine as an argument, and inside the subroutine it is declared as CHARACTER*(*), then
using the LEN(STRING) function in the subroutine retruns the actual string length passed in, and not the length of the string as declared in the calling program.
Example:
CHARACTER*1000 STRING
.
.
CALL SUBNAM(STRING(1:72)
SUBROUTINE SYBNAM(STRING)
CHARACTER*(*) STRING
LEN(STRING) will be 72, not 1000