I want to use a loop to step through each character of a string, checking for a digit or hyphen in the appropriate spots. For example, how would I check a phone number format like 604-000-0000?? Thanks.
Pseudo code to loop through a string to validate hyphen locations for a phone number of format 000-000-0000
for(i = 0; i < length of string; i++)
{
if((i is 3 or i is 7) and character at location i is a not hyphen)
{
print("non hyphen found at location " + i);
}
if((i is not 3 and i is not 7) and character at location i is not a digit)
{
print("non digit found at location " + i);
}
}
However this is almost certainly not the best way to validate a phone number. You should be either using an existing phone number validation method, or just write a simple Regular Expression.
Related
I got a question in vb.net
can I identify each of the character in string
for an example
i got a string of "Hello!. Good Afternoon!"
from this string can i trim away the period symbol?
Thank you
You should look at the methods of the String class, as they support different forms of string manipulation.
At its simplest, the Replace() method can be used to replace all occurrences of a period character with an empty string.
Alternatively, you can use the IndexOf() method to locate a specific string (e.g. the period) and the Remove() method to remove that character.
According to my 8-ball Magic, you actually want to :
Remove concecutive punctuation from a string:
With a Regex we are going to find all punctuation in the string.
The index of Match will be into an int[].
We will go iterate throught the array to find if the index is concecutive to the last punctuation index.
We will delete all the punctuation starting by the last one. Because starting with the 1rst will modify the index.
Code:
string Input = "....Thalassius! vero ea--*/-*/-- tempestate+- fectus";
string Output = Input;
var regex = new Regex(#"[^\w\s]|_"); // *1.
var matches = regex.Matches(Input) ;
var MatchesIndex = matches .Cast<Match>()
.Select(match => match.Index)
.ToArray(); // *2.
int last = 0;
List<int> toDelete = new List<int>();
for (int i = 0; i < MatchesIndex.Length; i++) // *3.
{
if ( MatchesIndex[i] == last + 1)
toDelete.Add(MatchesIndex[i]);
last = MatchesIndex[i];
}
foreach (int i in toDelete.OrderByDescending(x => x)) // *4.
Output = Output.Remove(i, 1);
Console.WriteLine("Input : " + Input);
Console.WriteLine("Output : " + Output);
C# Snippet
You can learn more about the regex used, thanks to #John Kugelman.
Writing a basic program to count the number of words in a string. I've changed my original code to account for multiple spaces between words. By setting one variable to the current index and one variable to the previous index and comparing them, I can say "if this current index is a space, but the previous index contains something other than a space (basically saying a character), then increase the word count".
int main(int argc, const char * argv[]) {
#autoreleasepool {
//establishing the string that we'll be parsing through.
NSString * paragraph = #"This is a test paragraph and we will be testing out a string counter.";
//we're setting our counter that tracks the # of words to 0
int wordCount = 0;
/*by setting current to a blank space ABOVE the for loop, when the if statement first runs, it's comparing [paragraph characterAtIndex:i to a blank space. Once the loop runs through for the first time, the next value that current will have is characterAtIndex:0, while the if statement in the FOR loop will hold a value of characterAtIndex:1*/
char current = ' ';
for (int i=0; i< paragraph.length; i++) {
if ([paragraph characterAtIndex:i] == ' ' && (current != ' ')) {
wordCount++;
}
current = [paragraph characterAtIndex:i];
//after one iteration, current will be T and it will be comparing it to paragraph[1] which is h.
}
wordCount ++;
NSLog(#"%i", wordCount);
}
return 0;
}
I tried adding "or" statements to account for delimiters such as ";" "," and "." instead of just looking at a space. It didn't work...any idea what I can do, logically speaking, to account for anything that isn't a letter (but preferably just limiting it to these four delimiters - . , ; and space.
A standard way to solve these types of problems is to build a finite state machine, your code isn't quite one but its close.
Instead of thinking about comparing the previous and current characters think in terms of states - you can start with just two, in a word and not in a word.
Now for each state you consider what the current character implies in terms of actions and changes to the state. For example, if the state is not in a word and the current character is a letter then the action is increment word count and the next state is in a word.
In (Objective-)C you can build a simple finite state machine using an enum to give the states names and a case statement inside a loop. In pseudo-code this is something like:
typedef enum { NotInWord, InWord } State;
State currentState = NotInWord;
NSUInteger wordCount = 0;
for currentChar in sourceString
case currentState of
NotInWord:
if currentChar is word start character -- e.g. a letter
then
increment wordCount;
currentState = InWord;
InWord:
if currentChar is not a word character -- e.g. a letter
then
currentState = NotInWord;
end case
end for
The above is just a step from your original algorithm - recasting it in terms of states rather than the previous character.
Now if you want to get smarter you can add more states. For example how many words are there in "Karan's question"? Two. So you might want to allow a single apostrophe in a word. To handle that you can add a state AfterApostrophe whose logic is the same as the current InWord; and modify InWord logic to include if the current character is an apostrophe the next state is AfterApostrophe - that would allow one apostrophe in a word (or its end, which is also valid). Next you might want to consider hyphenated words, etc...
To test if a character is a particular type you have two easy choices:
If this is just an exercise and you are happy to stick with the ASCII range of characters there are functions such as isdigit(), isletter() etc.
If you want to handle full Unicode you can use the NSCharacterSet type with its pre-defined sets for letters, digits, etc.
See the documentation for both of the above choices.
HTH
I don't understand, You should be able to add or statements....
int main(void) {
char paragraph[] = "This is a test paragraph,EXTRAWORDHERE and we will be testing out a string.";
char current = ' ';
int i;
int wordCount = 0;
for (i = 0; i < sizeof(paragraph); i++){
if ((paragraph[i] == 32 || paragraph[i] == 44) && !(current == 32 || current == 44)){ //32 = ascii for space, 44 for comma
wordCount++;
}
current = paragraph[i];
}
wordCount++;
printf("%d\n",wordCount);
return 0;
}
I suppose it would be better to change the comparison of current from a not equal to into an equal to. Hopefully that helps.
#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
#autoreleasepool {
int Number,rightDigit = 0;
NSLog(#"Enter the Number");
scanf("%d",&Number);
while (Number != 0) {
rightDigit = Number % 10;
printf("%d",rightDigit);
Number = Number / 10;
}
printf("\nright number is %d",rightDigit);
printf("\n number is %d",Number);
}
return 0;
}
I have reversed the number that the user had entered and i have to reverse it again so that it becomes what it was before.
For example: i typed 123 and it reversed it 321 and i want to reverse it again so it becomes 123 again.
how can i get my reversed number in integer variable?
How can i do that?
Let's look at how you reverse:
You take a copy of the rightmost digit by using %
You then "shift right" your number, using /, and the rightmost digit drops off
Display the copy of the rightmost digit you've extracted
Repeat till done
Now you want to create a new number which is the reverse of the original. Following your above algorithm pattern could you not:
"Shift left" the reversed number you are building up, introducing a new 0 digit at the right
Replace the just inserted rightmost 0 with the digit you wish to insert
Repeat
Each of these steps just requires a simple operation like your first algorithm, and you can combine both loops into one so you construct your reversed number instead of (or as well as) printing it out.
HTH
Here's what I'm trying to do. A user can type in a search string, which can include '*' or '?' wildcard characters. I'm finding this works with regular strings but not with ones including numeric characters.
e.g:
414D512052524D2E535441524B2E4E45298B8751202AE908
1208
if I look for a section of that hex string, it returns false. If I look for "120" or "208" in the "1208" string it fails.
Right now, my regular expression pattern ends up looking like this when a user enters, say "w?f": '\bw.?f\b'
I'm (obviously) not well-versed in regular expressions at the moment, but would appreciate any pointers someone may have to handle numeric characters in the way I need to - thanks!
Code in question:
/**
*
* #param searchString
* #param strToBeSearched
* #return
*/
public boolean findString(String searchString, String strToBeSearched) {
Pattern pattern = Pattern.compile(wildcardToRegex(searchString));
return pattern.matcher(strToBeSearched).find();
}
private String wildcardToRegex(String wildcard){
StringBuffer s = new StringBuffer(wildcard.length());
s.append("\\b");
for (int i = 0, is = wildcard.length(); i < is; i++) {
char c = wildcard.charAt(i);
switch(c) {
case '*':
s.append(".*");
break;
case '?':
s.append(".?");
break;
default:
s.append(c);
break;
}
}
s.append("\\b");
return(s.toString());
}
Let's assume your string to search in is
1208
The search "term" the user enters is
120
The pattern then is
\b120\b
The \b (word boundary) meta-character matches beginning and end of "words".
In our example, this can't work because 120 != 1208
The pattern has to be
\b.*120.*\b
where .* means match a variable number of characters (including null).
Solution:
either add the .*s to your wildcardToRegex(...) method to make this functionality work out-of-the-box,
or tell your users to search for *120*, because your * wildcard character does exactly the same.
This is, in fact, my preference because the user can then define whether to search for entries starting with something (search for something*), including something (*something*), ending with something (*something), or exactly something (something).
I really unable to find any workaround for regular expression to input price in decimal.
This what I want:-
12345
12345.1
12345.12
12345.123
.123
0.123
I also want to restrict digits.
I really created one but not validating as assumed
^([0-9]{1,5}|([0-9]{1,5}\.([0-9]{1,3})))$
Also want to know how is above expression different from the one
^([0-9]{1,5}|([0-9].([0-9]{1,3})))$ thats working fine.
Anyone with good explanation.
"I am using NSRegularExpression - Objective C" if this helps to answer more precisely
- (IBAction)btnTapped {
NSRegularExpression * regex = [NSRegularExpression regularExpressionWithPattern:
#"^\\d{1,5}([.]\\d{1,3})?|[.]\\d{1,3}$" options:NSRegularExpressionCaseInsensitive error:&error];
if ([regex numberOfMatchesInString:txtInput.text options:0 range:NSMakeRange(0, [txtInput.text length])])
NSLog(#"Matched : %#",txtInput.text);
else
NSLog(#"Not Matched : %#",txtInput.text);
}
"I am doing it in a buttonTap method".
This simple one should suit your needs:
\d*[.]?\d+
"Digits (\d+) that can be preceded by a dot ([.]?), which can itself be preceded by digits (\d*)."
Since you're talking about prices, neither scientific notation nor negative numbers are necessary.
Just as a point of interest, here's the one I usually used, scientific notation and negative numbers included:
[-+]?\d*[.]?\d+(?:[eE][-+]?\d+)?
For the new requirements (cf. comments), you can't specify how many digits you want on the first regex I gave, since it's not the way it has been built.
This one should suit your needs better:
\d{1,5}([.]\d{1,3})?|[.]\d{1,3}
"Max 5 digits (\d{1,5}) possibly followed ((...)?) by a dot itself followed by max 3 digits ([.]\d{1,3}), or (|) simply a dot followed by max 3 digits ([.]\d{1,3})".
Let's do this per-partes:
Sign in the beginning: [+-]?
Fraction number: \.\d+
Possible combinations (after sign):
Number: \d+
Fraction without zero \.\d+
And number with fraction: \d+\.\d+
So to join it all together <sign>(number|fraction without zero|number with fraction):
^[+-]?(\d+|\.\d+|\d+\.\d+)$
If you're not restricting the lengths to 5 digits before the decimal and 3 digits after then you could use this:
^[+-]?(?:[0-9]*\.[0-9]|[0-9]+)$
If you are restricting it to 5 before and 3 after max then you'd need something like this:
^[+-]?(?:[0-9]{0,5}\.[0-9]{1,3}|[0-9]{1,5})$
As far as the difference between your regexes goes, the first one limits the length of the number of digits before the decimal marker to 1-5 with and without decimals present. The second one only allows a single digit in front of the decimal pointer and 1-5 digits if there is no decimal.
How about this: ^([+-])?(\d+)?([.,])?(\d+)?$
string input = "bla";
if (!string.IsNullOrWhiteSpace(input))
{
string pattern = #"^(\s+)?([-])?(\s+)?(\d+)?([,.])?(\d+)(\s+)?$";
input = input.Replace("\'", ""); // Remove thousand's separator
System.Text.RegularExpressions.Regex.IsMatch(input, pattern);
// if server culture = de then reverse the below replace
input = input.Replace(',', '.');
}
Edit:
Oh oh - just realized that's where we run into a little bit of a problem if an en-us user uses ',' as thousand's separator....
So here a better one:
string input = "+123,456";
if (!string.IsNullOrWhiteSpace(input))
{
string pattern = #"^(\s+)?([+-])?(\s+)?(\d+)?([.,])?(\d+)(\s+)?$";
input = input.Replace(',', '.'); // Ensure no en-us thousand's separator
input = input.Replace("\'", ""); // Remove thousand's separator
input = System.Text.RegularExpressions.Regex.Replace(input, #"\s", ""); // Remove whitespaces
bool foo = System.Text.RegularExpressions.Regex.IsMatch(input, pattern);
if (foo)
{
bool de = false;
if (de) // if server-culture = de
input = input.Replace('.', ',');
double d = 0;
bool bar = double.TryParse(input, out d);
System.Diagnostics.Debug.Assert(foo == bar);
Console.WriteLine(foo);
Console.WriteLine(input);
}
else
throw new ArgumentException("input");
}
else
throw new NullReferenceException("input");
Edit2:
Instead of going through the hassle of getting the server culture, just use the tryparse overload with the culture and don't resubstitute the decimal separator.
double.TryParse(input
, System.Globalization.NumberStyles.Any
, new System.Globalization.CultureInfo("en-US")
, out d
);