I have to convert a backslash string into char, but it seems that casting doesn't exist like in java:
String msg = (Char) new_msg
I have to convert string values like "\t", "\n", "\000"-"\255" to char.
I would first start questioning why you have a single character string in the first place, and whether you can be sure that that is what you actually have. But given that it is, you can get a char from a string, whether it's in the first position or any other, using either String.get, or the more convenient string indexing operator:
let s = "\t"
let c: char = String.get s 0
let c: char = s.[0]
But note that these will both raise an Invalid_argument exception if there is no character at that position, such as if the string is empty, for example.
As an addendum to glennsl's answer, both methods will raise an Invalid_argument exception if the string is empty. If you were writing a function to get the first char of a string, you might use the option type to account for this.
let first_char_of_string s =
try Some s.[0]
with Invalid_argument _ -> None
Related
I have a string = "1337" and I want to convert it to a list of Int, I tried to get every element in the string and convert it to Int like this string[0].toInt but I didn't get the number I get the Ascii value, I can do it with this Character.getNumericValue(number), How I do it without using a built it function? with good complexity?
What do you mean "without using a built in function"?
string[0].toInt gives you the ASCII value of the character because the fun get(index: Int) on String has a return type of Char, and a Char behaves closer to a Number than a String. "0".toInt() == 0 will yield true, but '0'.toInt() == 0 will yield false. The difference being the first one is a string and the second is a character.
A oneliner
string.split("").filterNot { it.isBlank() }.map { it.toInt() }
Explanation: split("") will take the string and give you a list of every character as a string, however, it will give you an empty string at the beginning, which is why we have filterNot { it.isBlank() }, we then can use map to transform every string in our list to Int
If you want something less functional and more imperative that doesn't make use of functions to convert there is this
val ints = mutableListOf<Int>() //make a list to store the values in
for (c: Char in "1234") { //go through all of the characters in the string
val numericValue = c - '0' //subtract the character '0' from the character we are looking at
ints.add(numericValue) //add the Int to the list
}
The reason why c - '0' works is because the ASCII values for the digits are all in numerical order starting with 0, and when we subtract one character from another, we get the difference between their ASCII values.
This will give you some funky results if you give it a string that doesn't have only digits in it, but it will not throw any exceptions.
As in Java and by converting Char to Int you get the ascii equivalence.
You can instead:
val values = "1337".map { it.toString().toInt() }
println(values[0]) // 1
println(values[1]) // 3
// ...
Maybe like this? No-digits are filtered out. The digits are then converted into integers:
val string = "1337"
val xs = string.filter{ it.isDigit() }.map{ it.digitToInt() }
Requires Kotlin 1.4.30 or higher and this option:
#OptIn(ExperimentalStdlibApi::class)
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 need to split a uint to a list of bits (list of chars, where every char is "0" or "1", is also Ok). The way I try to do it is to concatenate the uint into string first, using binary representation for numeric types - bin(), and then to split it using str_split_all():
var num : uint(bits:4) = 0xF; // Can be any number
print str_split_all(bin(num), "/w");
("/w" is string match pattern that means any char).
The output I expect:
"0"
"b"
"1"
"1"
"1"
"1"
But the actual output is:
0. "0b1111"
Why doesn't it work? Thank you for your help.
If you want to split an integer into a list of bits, you can use the %{...} operator:
var num_bits : list of bit = %{num};
You can find a working example on EDAPlayground.
As an extra clarification to your question, "/w" doesn't mean match any character. The string "/\w/" means match any single character in AWK Syntax. If you put that into your match expression, you'll get (almost) the output you want, but with some extra blanks interleaved (the separators).
Regardless, if you want to split a string into its constituting characters, str_split_all(...) isn't the way to go. It's easier to convert the string into ASCII characters and then convert those back to string again:
extend sys {
run() is also {
var num : uint(bits:4) = 0xF; // Can be any number
var num_bin : string = bin(num);
var num_bin_chars := num_bin.as_a(list of byte);
for each (char) in num_bin_chars {
var char_as_string : string;
unpack(packing.low, %{8'b0, char}, char_as_string);
print char_as_string;
};
};
};
The unpack(...) syntax is directly from the e Reference Manual, Section 2.8.3 Type Conversion Between Strings and Scalars or Lists of Scalars
I am a novice programmer and I am trying to compare two characters from different strings, such that I can give an arbitrary index from each string and check to see if they match. From the processing website it seems that you can compare two strings, which I have done, but when I try to do so with characters it seems that the arguments (char,char) are not applicable. Can someone tell me where I am going wrong? Thanks.
You can use String's charAt() method/function to get character from each string at the desired index, then simply compare:
String s1 = ":)";
String s2 = ";)";
void setup(){
println(CompareCharAt(s1,s2,0));
println(CompareCharAt(s1,s2,1));
}
boolean CompareCharAt(String str1,String str2,int index){
return s1.charAt(index) == s2.charAt(index);
}
Note that when you're comparing strings == doesn't help, you need to use String's equal()
String s1 = ":)";
String s2 = ";)";
println(s1.equals(s2));
println(s1.equals(":)"));
Also, if data comes from external sources, it's usually a good idea to compare both strings at using the same case:
println("MyString".equals("myString"));
println("MyString".toLowerCase().equals("myString".toLowerCase()));
maybe you can pass the argument after converting(typecasting) the char to string.
(string(char),string(char))
Yep. Just use == as it gets interpreted as a char datatype.
This is assuming you've split the char from the String...
char a = 'a';
char b = 'a';
if(a == b) {
// etc
}
As mentioned above, use .equals() for String comparison.
String a = "a";
String b = "a";
if(a.equals(b)) {
// etc
}
Also, the proper way to cast a char as a String is str() not string()
I want to convert a char to a String in the following way:
char aaa = '\uE001';
I want to obtain a string with the value of "\uE001" so I can use substring(2) to obtain only "E001". Is that possible? Please help
Well, the character itself is a single character, U+E001. It has the hex value 0xE001. If you want that value as an integer, just use:
int unicodeValue = aaa;
You can then convert that integer value to hex in various ways, if you really need to, for example:
String hex = Integer.toString(unicodeValue, 16);
(That's assuming that overload is available on java-me.)
... or Integer.toHexString if that's available but Integer.toString(int, int) isn't.
Why do you want this value though? If you could clarify that, we may be able to give you more useful advice.
Integer.toHexString((int)aaa) ;
..and no substring() required.
This is the simple like that
char aaa = '\uE001';
String s=String.valueOf(aaa);
You can take any integer value and create a hex string from it like this:
String s = Integer.toHexString(num);
so Jon Skeet is on the right track. You can:
char aaa = '\uE001';
int num = aaa;
String hex = Integer.toHexString(num); //now contains "e001"