I want to convert c-style define names to camelcase.
Example: BLA_BLA -> blaBla
I created the following function:
private str camelCaseName(n) {
rVal = n;
if (contains(rVal, "_")) {
rVal = toLowerCase(rVal);
for (pos <- findAll(rVal, "_")) {
up = toUpperCase(stringChar(charAt(rVal, pos + 1)));
charList = chars(rVal);
charList = delete(charList, pos + 1);
charList = insertAt(charList, pos + 1, charAt(up, 0));
rVal = stringChars(charList);
}
// rVal = replaceAll(rVal, "_", "");
}
return rVal;
}
This works well for changing the case. However if I uncomment the replaceAll then a call that uses the string reports "Expected str, but got tuple[value,value,value]".
I guess there is an easier way to get this functionality.
I'm not sure what goes wrong with the replaceAll function, but I'd try the static checker on this code and read its error message.
Another way of writing the function:
private str camelCaseName(str n) {
words = split("_", toLowerCase(n));
return "<words[0]><for (w <- words[1..]) {><capitalize(w)><}>";
}
I added a type to the parameter n, that's obligatory.
String templates are a nice way of printing out stuff in a string.
The split function is handy; it splits a string into list elements.
The capitalize function changes the first letter of a word to a capital
Related
How can I add a method to the string table and modify self inside it ?
Basically, I'm trying to mimic the behaviour of the io.StringIO.read method in python, which reads n char in the string and returns them, modifying the string by "consuming" it.
I tried this:
function string.read(str, n)
to_return = str:sub(1, n)
str = str:sub(n + 1)
return to_return
end
local foo = "heyfoobarhello"
print(string.read(foo, 3))
print(foo)
Output is:
hey
heyfoobarhello
I expected the second line to be only foobarhello.
How can I achieve this ?
To mimic Python's io.StringIO class, you must make an object that stores both the underlying string and the current position within that string. Reading from an IO stream normally does not modify the underlying data.
local StringIO_mt = {
read = function(self, n)
n = n or #self.buffer - self.position + 1
local result = self.buffer:sub(self.position, self.position + n - 1)
self.position = self.position + n
return result
end,
}
StringIO_mt.__index = StringIO_mt
local function StringIO(buffer)
local o = {buffer = buffer, position = 1}
setmetatable(o, StringIO_mt)
return o
end
local foo = StringIO"heyfoobarhello"
print(foo:read(3))
print(foo:read())
Output:
hey
foobarhello
I don't recommend adding this class or method to Lua's string library, because the object has to be more complex than just a string.
You can add methods to the datatype string independently from the string table.
Short example that shows that the string methods even work if string table gets deleted...
string=nil
return _VERSION:upper():sub(1,3)
-- Returning: LUA
So you can add a method...
-- read.lua
local read = function(self, n1, n2)
return self:sub(n1, n2)
end
getmetatable(_VERSION).__index.read=read
return read
...for all strings.
( Not only _VERSION )
And use it...
do require('read') print(_VERSION:read(1,3):upper()) end
-- Print out: LUA
I am trying to convert following code into Java 8::
String s = "12345";
Map<Character,Integer> map = new HashMap<Character,Integer>();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (map.containsKey(c)) {
int cnt = map.get(c);
map.put(c, ++cnt);
} else {
map.put(c, 1);
}
}
I tried and found following way to iterate:
IntStream.rangeClosed(0, s.length).foreach(d -> {
//all statements from char to map.put
}) ;
I am not sure whether this is correct way to do it.
You can do this:
s.chars()
.mapToObj(x -> (char) x)
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
.mapToObj(x -> (char) x) is necessary because .chars() gives you a stream of ints, but in order to use groupingBy you need to work with objects, not primitives
groupingBy receives a function to get the key to group by and a Collector implementation
Function.identity() is just a function that returns whatever element it is passed to it
Collectors.counting() is a collector that counts
You can use the groupingBy() and counting() collectors:
String s = "12345";
Map<Character, Long> map = s
.chars()
.mapToObj(i -> (char) i)
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
System.out.println(map);
Unfortunately, there seems to be no convenient way to get a Stream<Character> from a string, hence the need to map to an IntStream using chars() and then using mapToObj() to convert it to a character stream.
I want convert string to Map in grails. I already have a function of string to map conversion. Heres the code,
static def StringToMap(String reportValues){
Map result=[:]
result=reportValues.replace('[','').replace(']','').replace(' ','').split(',').inject([:]){map,token ->
List tokenizeStr=token.split(':');
tokenizeStr.size()>1?tokenizeStr?.with {map[it[0]?.toString()?.trim()]=it[1]?.toString()?.trim()}:tokenizeStr?.with {map[it[0]?.toString()?.trim()]=''}
map
}
return result
}
But, I have String with comma in the values, so the above function doesn't work for me. Heres my String
[program_type:, subsidiary_code:, groupName:, termination_date:, effective_date:, subsidiary_name:ABC, INC]
my function returns ABC only. not ABC, INC. I googled about it but couldnt find any concrete help.
Generally speaking, if I have to convert a Stringified Map to a Map object I try to make use of Eval.me. Your example String though isn't quite right to do so, if you had the following it would "just work":
// Note I have added '' around the values.
String a = "[program_type:'', subsidiary_code:'', groupName:'', termination_date:'', effective_date:'', subsidiary_name:'ABC']"
Map b = Eval.me(a)
// returns b = [program_type:, subsidiary_code:, groupName:, termination_date:, effective_date:, subsidiary_name:ABC]
If you have control of the String then if you can create it following this kind of pattern, it would be the easiest solution I suspect.
In case it is not possible to change the input parameter, this might be a not so clean and not so short option. It relies on the colon instead of comma values.
String reportValues = "[program_type:, subsidiary_code:, groupName:, termination_date:, effective_date:, subsidiary_name:ABC, INC]"
reportValues = reportValues[1..-2]
def m = reportValues.split(":")
def map = [:]
def length = m.size()
m.eachWithIndex { v, i ->
if(i != 0) {
List l = m[i].split(",")
if (i == length-1) {
map.put(m[i-1].split(",")[-1], l.join(","))
} else {
map.put(m[i-1].split(",")[-1], l[0..-2].join(","))
}
}
}
map.each {key, value -> println "key: " + key + " value: " + value}
BTW: Only use eval on trusted input, AFAIK it executes everything.
You could try messing around with this bit of code:
String tempString = "[program_type:11, 'aa':'bb', subsidiary_code:, groupName:, termination_date:, effective_date:, subsidiary_name:ABC, INC]"
List StringasList = tempString.tokenize('[],')
def finalMap=[:]
StringasList?.each { e->
def f = e?.split(':')
finalMap."${f[0]}"= f.size()>1 ? f[1] : null
}
println """-- tempString: ${tempString.getClass()} StringasList: ${StringasList.getClass()}
finalMap: ${finalMap.getClass()} \n Results\n finalMap ${finalMap}
"""
Above produces:
-- tempString: class java.lang.String StringasList: class java.util.ArrayList
finalMap: class java.util.LinkedHashMap
Results
finalMap [program_type:11, 'aa':'bb', subsidiary_code:null, groupName:null, termination_date:null, effective_date:null, subsidiary_name:ABC, INC:null]
It tokenizes the String then converts ArrayList by iterating through the list and passing each one again split against : into a map. It also has to check to ensure the size is greater than 1 otherwise it will break on f[1]
I would like to convert the string containing abc to a list of characters and a hashset of characters. How can I do that in Java ?
List<Character> charList = new ArrayList<Character>("abc".toCharArray());
In Java8 you can use streams I suppose.
List of Character objects:
List<Character> chars = str.chars()
.mapToObj(e->(char)e).collect(Collectors.toList());
And set could be obtained in a similar way:
Set<Character> charsSet = str.chars()
.mapToObj(e->(char)e).collect(Collectors.toSet());
You will have to either use a loop, or create a collection wrapper like Arrays.asList which works on primitive char arrays (or directly on strings).
List<Character> list = new ArrayList<Character>();
Set<Character> unique = new HashSet<Character>();
for(char c : "abc".toCharArray()) {
list.add(c);
unique.add(c);
}
Here is an Arrays.asList like wrapper for strings:
public List<Character> asList(final String string) {
return new AbstractList<Character>() {
public int size() { return string.length(); }
public Character get(int index) { return string.charAt(index); }
};
}
This one is an immutable list, though. If you want a mutable list, use this with a char[]:
public List<Character> asList(final char[] string) {
return new AbstractList<Character>() {
public int size() { return string.length; }
public Character get(int index) { return string[index]; }
public Character set(int index, Character newVal) {
char old = string[index];
string[index] = newVal;
return old;
}
};
}
Analogous to this you can implement this for the other primitive types.
Note that using this normally is not recommended, since for every access you
would do a boxing and unboxing operation.
The Guava library contains similar List wrapper methods for several primitive array classes, like Chars.asList, and a wrapper for String in Lists.charactersOf(String).
The lack of a good way to convert between a primitive array and a collection of its corresponding wrapper type is solved by some third party libraries. Guava, a very common one, has a convenience method to do the conversion:
List<Character> characterList = Chars.asList("abc".toCharArray());
Set<Character> characterSet = new HashSet<Character>(characterList);
Use a Java 8 Stream.
myString.chars().mapToObj(i -> (char) i).collect(Collectors.toList());
Breakdown:
myString
.chars() // Convert to an IntStream
.mapToObj(i -> (char) i) // Convert int to char, which gets boxed to Character
.collect(Collectors.toList()); // Collect in a List<Character>
(I have absolutely no idea why String#chars() returns an IntStream.)
The most straightforward way is to use a for loop to add elements to a new List:
String abc = "abc";
List<Character> charList = new ArrayList<Character>();
for (char c : abc.toCharArray()) {
charList.add(c);
}
Similarly, for a Set:
String abc = "abc";
Set<Character> charSet = new HashSet<Character>();
for (char c : abc.toCharArray()) {
charSet.add(c);
}
List<String> result = Arrays.asList("abc".split(""));
Create an empty list of Character and then make a loop to get every character from the array and put them in the list one by one.
List<Character> characterList = new ArrayList<Character>();
char arrayChar[] = abc.toCharArray();
for (char aChar : arrayChar)
{
characterList.add(aChar); // autoboxing
}
You can do this without boxing if you use Eclipse Collections:
CharAdapter abc = Strings.asChars("abc");
CharList list = abc.toList();
CharSet set = abc.toSet();
CharBag bag = abc.toBag();
Because CharAdapter is an ImmutableCharList, calling collect on it will return an ImmutableList.
ImmutableList<Character> immutableList = abc.collect(Character::valueOf);
If you want to return a boxed List, Set or Bag of Character, the following will work:
LazyIterable<Character> lazyIterable = abc.asLazy().collect(Character::valueOf);
List<Character> list = lazyIterable.toList();
Set<Character> set = lazyIterable.toSet();
Bag<Character> set = lazyIterable.toBag();
Note: I am a committer for Eclipse Collections.
IntStream can be used to access each character and add them to the list.
String str = "abc";
List<Character> charList = new ArrayList<>();
IntStream.range(0,str.length()).forEach(i -> charList.add(str.charAt(i)));
Using Java 8 - Stream Funtion:
Converting A String into Character List:
ArrayList<Character> characterList = givenStringVariable
.chars()
.mapToObj(c-> (char)c)
.collect(collectors.toList());
Converting A Character List into String:
String givenStringVariable = characterList
.stream()
.map(String::valueOf)
.collect(Collectors.joining())
To get a list of Characters / Strings -
List<String> stringsOfCharacters = string.chars().
mapToObj(i -> (char)i).
map(c -> c.toString()).
collect(Collectors.toList());
So, using Foundation you can use NSCharacterSet to define character sets and test character membership in Strings. I would like to do so without Cocoa classes, but in a purely Swift manner.
Ideally, code could be used like so:
struct ReservedCharacters: CharacterSet {
characters "!", "#", "$", "&", ... etc.
func isMember(character: Character) -> Bool
func encodeCharacter(parameters) { accepts a closure }
func decodeCharacter(parameters) { accepts a closure }
}
This is probably a very loaded question. But I'd like to see what you Swifters think.
You can already test for membership in a character set by initializing a String and using the contains global function:
let vowels = "aeiou"
let isVowel = contains(vowels, "i") // isVowel == true
As far as your encode and decode functions go, are you just trying to get the 8-bit or 16-bit encodings for the Character? If that is the case then just convert them to a String and access there utf8 or utf16 properties:
let char = Character("c")
let a = Array(String(char).utf8)
println() // This prints [99]
Decode would take a little more work, but I know there's a function for it...
Edit: This will replace a character from a characterSet with '%' followed by the character's hex value:
let encode: String -> String = { s in
reduce(String(s).unicodeScalars, "") { x, y in
switch contains(charSet, Character(y)) {
case true:
return x + "%" + String(y.value, radix: 16)
default:
return x + String(y)
}
}
}
let badURL = "http://why won't this work.com"
let encoded = encode(badURL)
println(encoded) // prints "http://why%20won%27t%20this%20work.com"
Decoding, again, is a bit more challenging, but I'm sure it can be done...