How can I get 5 random strings in array? I tried this:
stringsArray = [[NSMutableArray alloc]init];
int string_lenght = 10;
NSString *symbols = #"ABCDEFGHIJKLMNOPQRSTUWXYZabcdefghijklmnopqrstuvwxyz";
NSMutableString *randomString = [NSMutableString stringWithCapacity:string_lenght];
for (int y = 0; y<5; y++) {
for (int i = 0; i<string_lenght; i++) {
[randomString appendFormat:#"%C", [symbols characterAtIndex:random()%[symbols length]]];
}
stringsArray = [NSMutableArray arrayWithObject:randomString];
}
But after I run this, all I have is one long random string!
You almost had it. I think this should work, but I haven't tested it.
stringsArray = [[NSMutableArray alloc] init];
int string_length = 10;
NSString *symbols = #"ABCDEFGHIJKLMNOPQRSTUWXYZabcdefghijklmnopqrstuvwxyz";
for (int y = 0; y < 5; y++)
{
//Allocate a new "randomString" object each time, or you'll just add to the old one
NSMutableString *randomString = [NSMutableString stringWithCapacity:string_length];
for (int i = 0; i < string_length; i++)
{
char c = [symbols characterAtIndex:random() % [symbols length]];
[randomString appendFormat:#"%c", c];
}
//Add the object to the array instead of replacing the entire array
[stringsArray addObject:randomString];
}
you are setting the strings array each time, change
stringsArray = [NSMutableArray arrayWithObject:randomString];
to
[stringsArray addObject:randomString];
and you should move the randomString initialisation into the for loop, or you will be appending new random characters to the same string
Related
I want to combine the array values into one string.
my arrays are like...
array1=[#"fizan",#"nike",#"pogo"];
array2=[#"round",#"rectangle",#"square"];
array3=[#"frame",#"frame",#"frame"];
I need like this...
value1 = fizan round frame
value2 = nike rectangle frame
value3 = pogo square frame
try this:
NSArray *array1= #[#"fizan",#"nike",#"pogo"];
NSArray *array2= #[#"round",#"rectangle",#"square"];
NSArray *array3= #[#"frame",#"frame",#"frame"];
NSMutableArray *array = [[NSMutableArray alloc] initWithArray:#[array1,array2,array3]];
NSMutableArray *output = [[NSMutableArray alloc] init];
NSString *a;
NSInteger count = array.count;
for (int i = 0; i<array1.count; i++) {
a = #"";
for (int j = 0; j<count; j++) {
a = [a isEqualToString: #""] ? [NSString stringWithFormat:#"%#",[[array objectAtIndex:j] objectAtIndex:i]] : [NSString stringWithFormat:#"%# %#",a,[[array objectAtIndex:j] objectAtIndex:i]];
}
[output addObject:a];
}
for (int i = 0; i < output.count; i++) {
NSLog(#"value %i -> %#",i+1,output[i]);
}
Hope this helps!
UPDATE:
NSArray *array1= #[#"fizan",#"",#"pogo"];
NSArray *array2= #[#"round",#"rectangle",#"square"];
NSArray *array3= #[#"frame",#"frame",#"frame"];
NSMutableArray *array = [[NSMutableArray alloc] initWithArray:#[array1,array2,array3]];
NSMutableArray *output = [[NSMutableArray alloc] init];
NSString *a;
NSInteger count = array.count;
for (int i = 0; i<array1.count; i++) {
a = #"";
for (int j = 0; j<count; j++) {
a = [a isEqualToString: #""] ? [NSString stringWithFormat:#"%#",[[array objectAtIndex:j] objectAtIndex:i]] : [NSString stringWithFormat:#"%# %#",a,[[array objectAtIndex:j] objectAtIndex:i]];
}
[output addObject:a];
}
for (int i = 0; i < output.count; i++) {
NSLog(#"value %i -> %#",i+1,output[i]);
}
I have tested this code. It works perfect. Check again and reconsider the issue.
Do this
NSArray *array1 = #[#"fizan", #"nike", #"pogo"];
NSString *value = [array1 componentsJoinedByString:#" "];
NSLog(#"value = %#", value);
Output will get like
value = fizan nike pogo
For your case
NSArray *completeArray = #[#[#"fizan",#"nike",#"pogo"], #[#"round",#"rectangle",#"square"], #[#"frame",#"frame",#"frame"]];
NSMutableArray *resultArray = [NSMutableArray array];
unsigned long count = 1;
for (int i = 0; i< count; i++) {
NSMutableArray *listArray = [NSMutableArray array];
for (NSArray *itemArray in completeArray) {
count = MAX(count,itemArray.count);
if (i < itemArray.count) {
[listArray addObject:itemArray[i]];
}
}
[resultArray addObject:listArray];
}
for (NSArray *itemArray in resultArray) {
NSString *value = [itemArray componentsJoinedByString:#" "];
NSLog(#"value = %#", value);
}
output
value = fizan round frame
value = nike rectangle frame
value = pogo square frame
I want to filter NSString from NSDictionary to load image but I still don't know how to do it even though I try many ways to achieve .
arr = [allJson allValues];
NSMutableArray *imagearray = [[NSMutableArray alloc]init];
for (int i = 0;i < arr.count; i++)
{
[imagearray addObject:arr[i][#"pic_url"]] ;
}
but when set breakpoint on the arr had 10 object
imagearray is 0 object
Here is my allJson data
"
allen = mock;
category = "\U5c71\U5be8/\U5632\U8af7";
clickRate = 618;
director = "\U5091\U745e\U5fb7\U5b54\U6069";
language = "\U82f1\U8a9e";
movieTime = 83;
"name_en" = "Atlantic Rim";
"name_zh" = "\U74b0\U5927\U897f\U6d0b";
nation = "\U7f8e\U570b";
"picH_url" = "http://api.dvacloud.com/pics/picH/1.jpg";
"pic_url" = "http://api.dvacloud.com/pics/1.jpg";
ranking = "\U4fdd\U8b77\U7d1a";
Follow the below code, It will work if you are having right json dictionary,
NSMutableArray *imagearray = [[NSMutableArray alloc]init];
for (int i = 0;i < arr.count; i++)
{
[imagearray addObject:[[arr objectAtIndex:i] valueForKey:#"pic_url"]];
}
Hope this will work for u.
What is the best algorithm to find all possible words from an array of array of character.
Here an example :
From this array : [[A],[B,C,D],[E,F],[G,H]]
I need in return an array of the 12 ordered possibilities [[A,B,E,G],[A,C,E,G], ... , [A,D,F,H]]
Do you know how to implement this algorithm ? If you know it and you provide an example in any language (C,JAVA,Javascript, ...), feel free to share because it's been a day I try to find it ...
Here how I tries to implement it ("array" is an array of array of char):
+ (NSArray*) possibleReading:(NSMutableArray*)array {
int nbPossibilities = 1;
for(int i = 0; i < [array count]; i++) {
nbPossibilities *=[[array objectAtIndex:i] count];
}
NSMutableArray *possArr = [[NSMutableArray alloc] initWithCapacity:nbPossibilities];
for (int i=0; i < nbPossibilities; i++) {
NSMutableArray *innerArray = [[NSMutableArray alloc] initWithCapacity:[array count]];
[possArr addObject:innerArray];
}
for (int i=0; i< [array count]; i++) {
//
for(int nbPoss = 0; nbPoss < nbPossibilities; nbPoss++) {
NSMutableArray * arr = [possArr objectAtIndex:nbPoss];
NSNumber * num = [NSNumber numberWithInt:nbPoss % [[array objectAtIndex:i] count]];
NSString * literal = [[array objectAtIndex:i] objectAtIndex:[num intValue]];
[arr insertObject:literal atIndex:i];
}
}
return possArr;
}
It would be easiest to do this using a recursive method.
Java code
import java.util.Arrays;
public class CartesianProductCalculator {
private char[][] result;
private char[][] sets;
private char[] currentSet;
private int index;
public char[][] calculateProduct(char[][] sets) {
index = 0;
// calculate size of result
int resultSize = 1;
this.sets = sets;
for (char[] set : sets) {
resultSize *= set.length;
}
result = new char[resultSize][];
currentSet = new char[sets.length];
calculateProduct(sets.length-1);
return result;
}
// fills result from right to left
public void calculateProduct(int setIndex) {
if (setIndex >= 0) {
for (char c : sets[setIndex]) {
currentSet[setIndex] = c;
calculateProduct(setIndex-1);
}
} else {
result[index++] = Arrays.copyOf(currentSet, currentSet.length);
}
}
public static void main(String[] args) {
char[][] input = {{'A'},{'B','C','D'},{'E','F'},{'G','H'}};
CartesianProductCalculator productCalculator = new CartesianProductCalculator();
System.out.println(Arrays.deepToString(productCalculator.calculateProduct(input)));
}
}
Objectiv-C
+ (NSArray *) cartesianProductOfArrays(NSArray *arrays) {
int arraysCount = arrays.count;
unsigned long resultSize = 1;
for (NSArray *array in arrays)
resultSize *= array.count;
NSMutableArray *product = [NSMutableArray arrayWithCapacity:resultSize];
for (unsigned long i = 0; i < resultSize; ++i) {
NSMutableArray *cross = [NSMutableArray arrayWithCapacity:arraysCount];
[product addObject:cross];
unsigned long n = i;
for (NSArray *array in arrays) {
[cross addObject:[array objectAtIndex:n % array.count]];
n /= array.count;
}
}
return product;
}
C
#include <stdio.h>
#include <string.h>
void print(int size, char *array[size], int indexs[size]){
char result[size+1];
int i;
for(i = 0; i < size; ++i)
result[i] = array[i][indexs[i]];
result[size] = 0;
puts(result);
}
int countUp(int size, int indexs[size], int lens[size]){
int i = size -1;
while(i >= 0){
indexs[i] += 1;// count up
if(indexs[i] == lens[i])
indexs[i--] = 0;
else
break;
}
return i >= 0;
}
void find_all(int size, char *array[size]){
int lens[size];
int indexs[size];
int i;
for(i = 0; i < size; ++i){//initialize
lens[i] = strlen(array[i]);
indexs[i] = 0;
}
do{
print(size, array, indexs);
}while(countUp(size, indexs, lens));
}
int main(void){
char *array[] = { "A", "BCD", "EF", "GH" };
int size = sizeof(array)/sizeof(*array);
find_all(size, array);
return 0;
}
If you can remove duplicate entries in inner array objects before executing method then you won't get duplicate words in result array.
- (NSArray*) possibleReading:(NSMutableArray*)array {
int nbPossibilities = 1;
for(int i = 0; i < [array count]; i++)
{
NSArray *cleanedArray = [[NSSet setWithArray:[array objectAtIndex:i]] allObjects];
[array replaceObjectAtIndex:i withObject:cleanedArray];
nbPossibilities *=[[array objectAtIndex:i] count];
}
NSMutableArray *possArr = [[NSMutableArray alloc] initWithCapacity:nbPossibilities];
for (int i=0; i < nbPossibilities; i++) {
NSMutableArray *innerArray = [[NSMutableArray alloc] initWithCapacity:[array count]];
[possArr addObject:innerArray];
}
for (int i=0; i< [array count]; i++) {
//
for(int nbPoss = 0; nbPoss < nbPossibilities; nbPoss++) {
NSMutableArray * arr = [possArr objectAtIndex:nbPoss];
NSNumber * num = [NSNumber numberWithInt:nbPoss % [[array objectAtIndex:i] count]];
NSString * literal = [[array objectAtIndex:i] objectAtIndex:[num intValue]];
[arr insertObject:literal atIndex:i];
}
}
return possArr;
}
I'm trying to get each individual character of a string, gameWord, into an NSMutableArray.
I'm converting each char into an object and then adding the objects into the NSMutableArray with the following code:
NSMutableString *letterOne = [[NSMutableString alloc] initWithFormat:#"%C",[gameWord characterAtIndex:0]];
NSMutableString *letterTwo = [[NSMutableString alloc] initWithFormat:#"%C",[gameWord characterAtIndex:1]];
and so on....
What I don't understand is why the following loop won't work?
NSMutableArray *lettersArray = [[NSMutableArray alloc] initWithCapacity:[gameWord length]];
for (int x = 0 ; x <= [gameWord length] ; x++) {
NSMutableString *letter = [[NSMutableString alloc]initWithFormat:#"%C",[gameWord characterAtIndex:x]];
[lettersArray addObject:letter];
[letter release];
}
Would really appreciate help understanding this problem and any other ways of getting each character of an NSString into individual objects (not chars).
Your for loop goes beyond the length of the string. Arrays are zero-based, so the last object has the index [gameWord length] - 1.
This should work:
for (int x = 0; x < [gameWord length]; x++) {
//... ^--changed from <= to <
}
I would like to select x amount of items randomly from a "list" in objective C store them in an other "list" (each item can only be selected one) , I'm talking about lists because I'm coming from Python. What would be the best way to store a list of strings in Objective C ?
cheers,
You should use NSMutableArray class for changeable arrays or NSArray for non-changeable ones.
UPDATE: a piece of code for selecting a number of items from an array randomly:
NSMutableArray *sourceArray = [NSMutableArray array];
NSMutableArray *newArray = [NSMutableArray array];
int sourceCount = 10;
//fill sourceArray with some elements
for(int i = 0; i < sourceCount; i++) {
[sourceArray addObject:[NSString stringWithFormat:#"Element %d", i+1]];
}
//and the magic begins here :)
int newArrayCount = 5;
NSMutableIndexSet *randomIndexes = [NSMutableIndexSet indexSet]; //to trace new random indexes
for (int i = 0; i < newArrayCount; i++) {
int newRandomIndex = arc4random() % sourceCount;
int j = 0; //use j in order to not rich infinite cycle
//tracing that all new indeces are unique
while ([randomIndexes containsIndex:newRandomIndex] || j >= newArrayCount) {
newRandomIndex = arc4random() % sourceCount;
j++;
}
if (j >= newArrayCount) {
break;
}
[randomIndexes addIndex:newRandomIndex];
[newArray addObject:[sourceArray objectAtIndex:newRandomIndex]];
}
NSLog(#"OLD: %#", sourceArray);
NSLog(#"NEW: %#", newArray);