I have a dynamic array. I need to display tableview as following scenario...
In the First cell i need to display 1 item.
In the second cell i need to display 2 items.
In the third cell i need to display 3 items.
In the forth cell i need to display 1 item.
In the fifth cell i need to display 2 items.
In the sixth cell i need to display 3 items.
and so on...
Could any one please suggest how to return no of rows in a section.
Try this :
int noOfRow = total/2 + ceil((total % 3)/3.0);
Simple logic for this is:
NoOfRows = TotalCount / 2
For e.g.:
If last value is 6 then, total no of rows are (6 / 2) = 3
If last value is 12 then, total no of rows are (12 / 2) = 6
You have to think logical that's it.
Hope this helps.
A faster method might be:
Notice in the divide by 2 method, most numbers work. The ones don't work are:
2, 4, 8, 10... basically, even numbers that aren't divisible by 6.
So we can come up with something like:
int count = array.count;
if (count % 2 == 0 && count % 6 != 0) {
count + 2;
}
int rows = ceilf(count / 2);
Or we can write a for loop:
int counter = array.size;
int rows = 0;
int dec = 1;
while (counter > 0) {
rows++;
counter - dec;
dec = dec % 3 + 1;
}
The for loop is of course, slower.
Related
Let's say I have a column of numbers:
1
2
3
4
5
6
7
8
Is there a formula that can calculate sum of numbers starting from n-th row and adding to the sum k numbers, for example start from 4th row and add 3 numbers down the row, i.e. PartialSum(4, 3) would be 4 + 5 + 6 = 15
BTW I can't use App Script as now it has some type of error Error code RESOURCE_EXHAUSTED. and in general I have had issue of stabile work with App Script before too.
As Tanaike mentioned, the error code when using Google Apps Script was just a temporary bug that seems to be solved at this moment.
Now, I can think of 2 possible solutions for this using custom functions:
Solution 1
If your data follows a specific numeric order one by one just like the example provided in the post, you may want to consider using the following code:
function PartialSum(n, k) {
let sum = n;
for(let i=1; i<k; i++)
{
sum = sum + n + i;
}
return sum;
}
Solution 2
If your data does not follow any particular order and you just want to sum a specific number of rows that follow the row you select, then you can use:
function PartialSum(n, k) {
let ss = SpreadsheetApp.getActiveSheet();
let r = ss.getRange(n, 1); // Set column 1 as default (change it as needed)
let sum = n;
for(let i=1; i<k; i++)
{
let val = ss.getRange(n + i, 1).getValue();
sum = sum + val;
}
return sum;
}
Result:
References:
Custom Functions in Google Sheets
Formula:
= SUM( OFFSEET( initialCellName, 0, 0, numberOfElementsInColumn, 0) )
Example add 7 elements starting from A5 cell:
= SUM( OFFSEET( A5, 0, 0, 7, 0) )
I'm trying to create a code that generates random numbers within the range 10-30 but making sure that no number is repeated. It shows "subscript out of range" on NumArray(Count) = Count when I run the code.
'Make an array of completely sorted numbers
FOR Count = 10 TO 30
NumArray(Count) = Count
NEXT Count
RANDOMIZE TIMER
FOR Count = 10 TO 30
Number = (RND * (31 - Count)) + 10
PRINT #1, NumArray(Number)
FOR Counter = Number TO 30 - Count
NumArray(Counter) = NumArray(Counter + 1)
NEXT Counter
NEXT Count
This isn't actually my code. Copied and pasted for my assignment.
It looks like you're missing some DIM statements.
Variables containing numbers have type SINGLE by default, so you might see something like FOR Counter = 18.726493 TO 20 because the RND function returns a number between 0 and 1, excluding 1, meaning you will be trying to use NumArray(18.726493) which will not work.
Arrays that are not explicitly declared can only have 11 items with an index from 0 to 10, but the range 10-30 requires you to store 21 items (30 - 10 + 1 = 21). You can also specify a custom upper and lower bound if it will make your code easier for you to understand. Add these lines before the first line in your code shown above:
DIM Number AS INTEGER
DIM NumArray(10 TO 30) AS INTEGER
This will ensure Number only contains integers (any fractional values are rounded to the nearest integer), and NumArray will work from NumArray(10) to NumArray(30), but you can't use NumArray(9), NumArray(8), NumArray(31), etc. The index must be in the range 10-30.
I think that should fix your code, but I don't know for certain since I don't fully understand how it is supposed to work. At the very least, it will fix the type and subscript problems in your code.
You need to declare the array:
'Make an array of completely sorted numbers
DIM NumArray(30) AS INTEGER
FOR Count = 10 TO 30
NumArray(Count) = Count
NEXT Count
RANDOMIZE TIMER
FOR Count = 10 TO 30
Number = (RND * (31 - Count)) + 10
PRINT #1, NumArray(Number)
FOR Counter = Number TO 30 - Count
NumArray(Counter) = NumArray(Counter + 1)
NEXT Counter
NEXT Count
I am learning how to make a multiplication table in swift and used
override func viewDidLoad() {
let n = Int(str)!
while (i<=10) {
let st = "\(n) * \(i) = \(n * i)"
lbl.text = st
i += 1
}
this code. i have a label in which i want to show the table, but the problem is that only the last result which is say 2*10 = 20 is showing and not all the other value. i am confused what to do, please help what to do so that all the values are displayed.
Glad you've decided to learn Swift. You're on the right track, but as others have said, your final iteration of the loop is replacing the contents of lbl.text.
There are many ways to achieve what you want, but for problems like this I'd suggest starting off working in a playground rather than worrying about labels, viewDidLoad and suchlike.
Here's a nice Swift-y way to do what you want
let n = 12
let table = Array(0...10).map({"\(n) * \($0) = \(n * $0)"}).joinWithSeparator("\n")
print("\(table)")
Gives…
12 * 0 = 0
12 * 1 = 12
12 * 2 = 24
12 * 3 = 36
12 * 4 = 48
12 * 5 = 60
12 * 6 = 72
12 * 7 = 84
12 * 8 = 96
12 * 9 = 108
12 * 10 = 120
To break that down…
// Take numbers 0 to 10 and make an array
Array(0...10).
// use the map function to convert each member of the array to a string
// $0 represents each value in turn.
// The result is an array of strings
map({"\(n) * \($0) = \(n * $0)"}).
// Join all the members of your `String` array with a newline character
joinWithSeparator("\n")
Try it for yourself. In Xcode, File -> New -> Playground, and just paste in that code. Good luck!
That's because every time the loop iterates, it overwrites the previous value in label.text. You need to append the new value to existing string value in label, as suggested by RichardG.
let n = Int(str)!
while (i<=10) {
let st = "\(n) * \(i) = \(n * i)"
lbl.text = lbl.text + " " +st //Append new value to already existing value in label.text
i += 1
}
There is also a possibility of UI issue. You have to provide number of lines to the label or it will mess up the display. It also needs to be of size enough to hold your data. A better option would be UITextView which is scrollable, if you are unwilling to handle cases for label height and width. But if you want to stick with UILabel, the following code will resize the label depending on text for you:
lbl.numberOfLines = 0; //You only need to call this once. Maybe in `viewDidLoad` or Storyboard itself.
lbl.text = #"Some long long long text"; //here you set the text to label
[lbl sizeToFit]; //You must call this method after setting text to label
You can also handle that by Autolayout constraints.
Easy way to do it with SWIFT 2.0
var tableOf = 2 //Change the table you want
for index in 1...10 {
print("\(tableOf) X \(index) = \(index * tableOf)")
}
OUTPUT
repeat-while loop, performs a single pass through the loop block first before considering the loop's condition (exactly what do-while loop does).
1) repeat...while Loop
var i = Int()
repeat {
print("\(i) * \(i) = \(i * 11)")
i += 1
} while i <= 11
2) While Loop
var i = Int()
while i <= 11
{
print("\(i) * \(i) = \(i * 11)")
i += 1
}
3) For Loop
for n in 1..<11
{
print("\(n) * \(n) = \(n * 10)")
}
I need to round a number, let's say 543 to either the hundreds or the tens place. It could be either one, as it's part of a game and this stage can ask you to do one or the other.
So for example, it could ask, "Round number to nearest tens", and if the number was 543, they would have to enter in 540.
However, I don't see a function that you can specify target place value to round at. I know there's an easy solution, I just can't think of one right now.
From what I see, the round function rounds the last decimal place?
Thanks
To rounding to 100's place
NSInteger num=543;
NSInteger deci=num%100;//43
if(deci>49){
num=num-deci+100;//543-43+100 =600
}
else{
num=num-deci;//543-43=500
}
To round to 10's place
NSInteger num=543;
NSInteger deci=num%10;//3
if(deci>4){
num=num-deci+100;//543-3+10 =550
}
else{
num=num-deci;//543-3=540
}
EDIT:
Tried to merge the above in one:
NSInteger num=543;
NSInteger place=100; //rounding factor, 10 or 100 or even more.
NSInteger condition=place/2;
NSInteger deci=num%place;//43
if(deci>=condition){
num=num-deci+place;//543-43+100 =600.
}
else{
num=num-deci;//543-43=500
}
You may just use an algorithm in your code:
For example, lets say that you need to round up a number to hundred's place.
int c = 543
int k = c % 100
if k > 50
c = (c - k) + 100
else
c = c - k
To round numbers, you can use the modulus operator, %.
The modulus operator gives you the remainder after division.
So 543 % 10 = 3, and 543 % 100 = 43.
Example:
int place = 10;
int numToRound=543;
// Remainder is 3
int remainder = numToRound%place;
if(remainder>(place/2)) {
// Called if remainder is greater than 5. In this case, it is 3, so this line won't be called.
// Subtract the remainder, and round up by 10.
numToRound=(numToRound-remainder)+place;
}
else {
// Called if remainder is less than 5. In this case, 3 < 5, so it will be called.
// Subtract the remainder, leaving 540
numToRound=(numToRound-remainder);
}
// numToRound will output as 540
NSLog(#"%i", numToRound);
Edit: My original answer was submitted before it was ready, because I accidentally hit a key to submit it. Oops.
Can I set a range of numbers when using arc4random()? For example 50-100 only.
As pointed out in other posts below, it is better to use arc4random_uniform. (When this answer was originally written, arc4random_uniform was not available). Besides avoiding the modulo bias of arc4random() % x, it also avoids a seeding problem with arc4random when used recursively in short timeframes.
arc4random_uniform(4)
will generate 0, 1, 2 or 3. Thus you could use:
arc4random_uniform(51)
and merely add 50 to the result to get a range between 50 & 100 (inclusive).
To expand upon JohnK comment.
It is suggested that you use the following function to return a ranged random number:
arc4random_uniform(51)
which will return a random number in the range 0 to 50.
Then you can add your lower bounds to this like:
arc4random_uniform(51) + 50
which will return a random number in the range 50 to 100.
The reason we use arc4random_uniform(51) over arc4random() % 51 is to avoid the modulo bias. This is highlighted in the man page as follows:
arc4random_uniform(upper_bound) will return a uniformly distributed random number less than upper_bound. arc4random_uniform() is recommended over constructions like ``arc4random() % upper_bound'' as it avoids "modulo bias" when the upper bound is not a power of two.
In short you get a more evenly distributed random number generated.
int fromNumber = 10;
int toNumber = 30;
int randomNumber = (arc4random()%(toNumber-fromNumber))+fromNumber;
Will generate randon number between 10 and 30, i.e. 11,12,13,14......29
You can use this code for generating random values with range:
//range from 50 to 100
int num1 = (arc4random() % 50) + 50; or
int num1 = arc4random_uniform(50) + 50;
//range from 0-100
int num1 = arc4random() % 100; or
int num1 = arc4random_uniform(100);
In Swift you can use this (inspired by answer of #Justyn)
func generateRandomKey(fromRange rangeFrom:Int, toRange rangeTo:Int) -> Int{
let theKey = arc4random_uniform(UInt32(rangeTo - rangeFrom)) + UInt32(rangeFrom)
return Int(theKey)
}
Will always give you a random range Integer.
In many situations 10 thru 30 would mean inclusive, (includes 10 and 30) ...
int fromNumber = 10;
int toNumber = 30;
toNumber ++;
int randomNumber = (arc4random()%(toNumber-fromNumber))+fromNumber;
Notice the difference toNumber - fromNumber is now 21 ... (20+1) which yields the possible results of 0 thru 20 (inclusive) which when added to fromNumber (10) results in 10 thru 30 (inclusive).