I have a string of numbers separated by commas. I would like to remove the first and last comma if it exists.
//qlist = ',6063,6077,6051,5925,6069,6054,6071,6049,5903,5858,5760,';
if (qlist.substring(qlist.length - 1) == ','){
qlist= qlist.substring(0,qlist.length - 1);
}
if (qlist.substring(0) == ','){
qlist= qlist.substring(1,qlist.length);
}
Please suggest the right approach.
You could do the following:
int startSlice = 0;
int endSlice = myString.length;
if (myString.startsWith(‘,’))
startSlice = 1;
if (myString.endsWith(‘,’))
endSlice -= 1;
myString = myString.subString(startSlice, endSlice);
Related
Edit
**After quite a bit of playing around with my code I have written few versions, one of them is what I sought for.
I'd do the following:
Create a helper Set with all the numbers from 1 to 100 - O(n) in time and space
Create an (initially) empty Set to record the indexes with 0s - O(1)
Go over the array - O(n):
If the value is 0, add the index to the index set
If the value isn't 0, remove it from the helper Set
Go over the helper set, and assign the remaining values to the indexes saved to the index set - O(m), where m<=n
All in all - an O(n) solution in time and space.
In java:
int[] numbers = /* the array with missing numbers */
Set<Integer> allNumbers = IntStream.rangeClosed(1, 100).boxed().Collect(Collectors.toSet());
Set<Ineteger> missingIndexes = new HashSet<>();
for (int i = 0; i < numbers.length; ++i) {
if (numbers[i] == 0) {
missingIndexes.add(i);
} else {
allNumbers.remove(i);
}
}
Iterator<Integer> numberIter = allNumbers.iterator();
Iterator<Integer> indexIter = missingIndexes.iterator();
while (numberIter.hasNext() && indexIter.hasNext()) {
numbers[indexIter.next()] = numberIter.next();
}
If you can sacrifice a little more space to optimize for time.
Basically just create another missing array and fill it with what's missing by traversing your helper array.
Modified your original solution.
int input [] = {5,6,0,3,0,2,1};
int output [] = new int[input.length];
boolean [] helper = new boolean[input.length];
for(int i = 0; i <input.length; i++)
{
if(input[i] != 0)
helper[i] = true;
}
int missing [] = new int[input.length];
int missingCount = 0;
for(int j = 0; j < helper.length; j++)
{
if(!helper[j]){
missing[missingCount++] = j;
}
}
missingCount = 0;
for(int j = 0; j < input.length; j++){
if(input[j]==0){
input[j]=missing[missingCount++];
}
}
Below code can find the missing element and add them back in O(n) complexity:
notFound - Will store index or location of input array having number
with zero
numberDetails - Contains details of numbers whether its present in
input array or not(true or false)
Example: input[3] = false means 4 (3+1) is not present in input array
, input[4] = true means 5 (4+1) is present in input array
int input[] = { 5, 6, 0, 3, 0, 2, 1 };
int notFound[] = new int[input.length];
boolean[] numberDetails = new boolean[input.length];
int notFoundIndex=0;
for(int i=0;i<input.length;i++) {
if(input[i]==0) {
notFound[notFoundIndex++]=i;
}
else {
numberDetails[input[i]-1]=true;
}
}
notFoundIndex=0;
for(int j=0;j<numberDetails.length;j++) {
if(!numberDetails[j]) {
input[notFound[notFoundIndex++]] = j+1;
}
}
System.out.println(Arrays.toString(input));
I'm currently converting C++ code to Swift and I've gotten stuck on one part. The parameter passed into the function is a string and the area where I'm stuck is when attempting to set a variable based on the second to last character of a string to check for a certain character.
The error shows up on this line:
line[i-1]
I've tried casting this value to an Int but this didn't work:
Int(line[i - 1])
I've also tried to see if the string's startIndex function which takes a Int would work but it didn't:
line.startIndex[i - 1]
Here is the full function:
func scanStringForSpecificCharacters(line: String){
var maxOpen: Int = 0;
var minOpen: Int = 0;
minOpen = 0;
maxOpen = 0;
var i = 0
while i < line.characters.count {
for character in line.characters {
//var c: Character = line[i];
if character == "(" {
maxOpen += 1;
if i == 0 || line[i - 1] != ":" {
minOpen += 1;
}
}
else if character == ")"{
minOpen = max(0,minOpen-1);
if i == 0 || line[i-1] != ":"{
maxOpen -= 1;
}
if maxOpen < 0{
break;
}
}
}
if maxOpen >= 0 && minOpen == 0{
print("YES")
}else{
print("NO")
}
}
}
Strings in Swift aren't indexed collections and instead you can access one of four different views: characters, UTF8, UTF16, or unicodescalars.
This is because Swift supports unicode, where an individual characters may actually be composed of multiple unicode scalars.
Here's a post that really helped me wrap my head around this: https://oleb.net/blog/2016/08/swift-3-strings/
Anyway, to answer you question you'll need to create an index using index(after:), index(before:), or index(_, offsetBy:).
In your case you'd want to do something like this:
line.index(line.endIndex, offsetBy: -2) // second to last character
Also, you'll probably find it easier to iterate directly using a String.Index type rather than Int:
let line = "hello"
var i = line.startIndex
while i < line.endIndex {
print(line[i])
i = line.index(after: i)
}
// prints ->
// h
// e
// l
// l
// o
Working with Strings in Swift was changed several times during it's evolution and it doesn't look like C++ at all. You cannot subscript string to obtain individual characters, you should use index class for that. I recommend you read this article:
https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/StringsAndCharacters.html
As already pointed out in the other answers, the compiler error
is caused by the problem that you cannot index a Swift String with
integers.
Another problem in your code is that you have a nested loop which is
probably not intended.
Actually I would try to avoid string indexing at all and only
enumerate the characters, if possible. In your case, you can
easily keep track of the preceding character in a separate variable:
var lastChar: Character = " " // Anything except ":"
for char in line.characters {
if char == "(" {
maxOpen += 1;
if lastChar != ":" {
minOpen += 1;
}
}
// ...
lastChar = char
}
Or, since you only need to know if the preceding character is
a colon:
var lastIsColon = false
for char in string.characters {
if char == "(" {
maxOpen += 1;
if !lastIsColon {
minOpen += 1;
}
}
// ...
lastIsColon = char == ":"
}
Another possible approach is to iterate over the string and a shifted
view of the string in parallel:
for (lastChar, char) in zip([" ".characters, line.characters].joined(), line.characters) {
// ...
}
As others have already explained, trying to index into Swift strings is a pain.
As a minimal change to your code, I would recommend that you just create an array of the characters in your line up front:
let linechars = Array(line.characters)
And then anywhere you need to index into the line, use linechars:
This:
if i == 0 || line[i-1] != ":" {
becomes:
if i == 0 || linechars[i-1] != ":" {
I want to first letter to be in upper case other in lower. But after ".", it must be upper again..
function firstToUpperCase( str ) {
return str.substr(0, 1).toUpperCase() + str.substr(1);
}
var str = 'prompt("Enter text to convert: ")
var Upcase = firstToUpperCase( str );
document.write(Upcase);
Here's a simplistic answer based on what you provided. It does not take whitespace into account following the period since you didn't mention that in the specs.
function firstToUpperCase(str) {
var parts = str.split(".");
for (i = 0; i < parts.length; i++) {
parts[i] = parts[i].substring(0, 1).toUpperCase() + parts[i].substring(1).toLowerCase();
}
return parts.join(".");
}
If you're trying to deal with sentences, something like this might be a little better, though it does not preserve exact whitespace:
function firstToUpperCase(str) {
var parts = str.split(".");
for (i = 0; i < parts.length; i++) {
sentence = parts[i].trim();
parts[i] = sentence.substring(0, 1).toUpperCase() + sentence.substring(1).toLowerCase();
}
return parts.join(". ");
In a given sentence i want to split into 10 character string. The last word should not be incomplete in the string. Splitting should be done based on space or , or .
For example:
this is ram.he works at mcity.
now the substring of 10 chars is,
this is ra.
but the output should be,
this is.
Last word should not be incomplete
You can use a regular expression that checks that the character after the match is not a word character:
string input = "this is ram.he";
Match match = Regex.Match(input, #"^.{0,10}(?!\w)");
string result;
if (match.Success)
{
result = match.Value;
}
else
{
result = string.Empty;
}
Result:
this is
An alternative approach is to build the string up token by token until adding another token would exceed the character limit:
StringBuilder sb = new StringBuilder();
foreach (Match match in Regex.Matches(input, #"\w+|\W+"))
{
if (sb.Length + match.Value.Length > 10) { break; }
sb.Append(match.Value);
}
string result = sb.ToString();
Not sure if this is the sort of thing you were looking for. Note that this could be done a lot cleaner, but should get you started ... (may want to use StringBuilder instead of String).
char[] delimiterChars = { ',', '.',' ' };
string s = "this is ram.he works at mcity.";
string step1 = s.Substring(0, 10); // Get first 10 chars
string[] step2a = step1.Split(delimiterChars); // Get words
string[] step2b = s.Split(delimiterChars); // Get words
string sFinal = "";
for (int i = 0; i < step2a.Count()-1; i++) // copy count-1 words
{
if (i == 0)
{
sFinal = step2a[i];
}
else
{
sFinal = sFinal + " " + step2a[i];
}
}
// Check if last word is a complete word.
if (step2a[step2a.Count() - 1] == step2b[step2a.Count() - 1])
{
sFinal = sFinal + " " + step2b[step2a.Count() - 1] + ".";
}
else
{
sFinal = sFinal + ".";
}
I have been given some file name which can be like
<filename>YYYYMMDD<fileextension>
some valid file names that will satisfy the above pattern are as under
xxx20100326.xls,
xxx2v20100326.csv,
x_20100326.xls,
xy2z_abc_20100326_xyz.csv,
abc.xyz.20100326.doc,
ab2.v.20100326.doc,
abc.v.20100326_xyz.xls
In what ever be the above defined case, I need to pick up the dates only. So for all the cases, the output will be 20100326.
I am trying to achieve the same but no luck.
Here is what I have done so far
string testdata = "x2v20100326.csv";
string strYYYY = #"\d{4}";
string strMM = #"(1[0-2]|0[1-9])";
string strDD = #"(3[0-1]|[1-2][0-9]|0[1-9])";
string regExPattern = #"\A" + strYYYY + strMM + strDD + #"\Z";
Regex regex = new Regex(regExPattern);
Match match = regex.Match(testdata);
if (match.Success)
{
string result = match.Groups[0].Value;
}
I am using c#3.0 and dotnet framework 3.5
Please help. It is very urgent
Thanks in advance.
Try this:
DateTime result = DateTime.MinValue;
System.Globalization.CultureInfo provider = System.Globalization.CultureInfo.InvariantCulture;
var testString = "x2v20100326.csv";
var format = "yyyyMMdd";
try
{
for (int i = 0; i < testString.Length - format.Length; i++)
{
if (DateTime.TryParseExact(testString.Substring(i, format.Length), format, provider, System.Globalization.DateTimeStyles.None, out result))
{
Console.WriteLine("{0} converts to {1}.", testString, result.ToString());
break;
}
}
}
catch (FormatException)
{
Console.WriteLine("{0} is not in the correct format.", testString);
}
This one fetches the last date in the string.
var re = new Regex("(?<date>[0-9]{8})");
var test = "asdf_wef_20100615_sdf.csv";
var datevalue = re.Match(test).Groups["date"].Value;
Console.WriteLine(datevalue); // prints 20100615
Characters \A and \Z - begin and end of the string respectivly.
I think you need pattern like:
string regExPattern = #"\A.*(?<FullDate>" + strYYYY + strMM + strDD + #").*\..*\Z";
".*" - any symbols at the begin
".*\..*" - any symbols before the dot, dot and any symbols after dot
And get a full date:
match.Groups["FullDate"]
You may need to group things in your month and day expressions:
((1[0-2])|(0[1-9))
((3[0-1])|([1-2][0-9])|(0[1-9]))