Java Code to validate a name field [duplicate] - java

I want regex to validate for only letters and spaces. Basically this is to validate full name. Ex: Mr Steve Collins or Steve Collins I tried this regex. "[a-zA-Z]+\.?" But didnt work. Can someone assist me please
p.s. I use Java.
public static boolean validateLetters(String txt) {
String regx = "[a-zA-Z]+\\.?";
Pattern pattern = Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(txt);
return matcher.find();
}

What about:
Peter Müller
François Hollande
Patrick O'Brian
Silvana Koch-Mehrin
Validating names is a difficult issue, because valid names are not only consisting of the letters A-Z.
At least you should use the Unicode property for letters and add more special characters. A first approach could be e.g.:
String regx = "^[\\p{L} .'-]+$";
\\p{L} is a Unicode Character Property that matches any kind of letter from any language

try this regex (allowing Alphabets, Dots, Spaces):
"^[A-Za-z\s]{1,}[\.]{0,1}[A-Za-z\s]{0,}$" //regular
"^\pL+[\pL\pZ\pP]{0,}$" //unicode
This will also ensure DOT never comes at the start of the name.

For those who use java/android and struggle with this matter try:
"^\\p{L}+[\\p{L}\\p{Z}\\p{P}]{0,}"
This works with names like
José Brasão

You could even try this expression ^[a-zA-Z\\s]*$ for checking a string with only letters and spaces (nothing else).
For me it worked. Hope it works for you as well.
Or go through this piece of code once:
CharSequence inputStr = expression;
Pattern pattern = Pattern.compile(new String ("^[a-zA-Z\\s]*$"));
Matcher matcher = pattern.matcher(inputStr);
if(matcher.matches())
{
//if pattern matches
}
else
{
//if pattern does not matches
}

please try this regex (allow only Alphabets and space)
"[a-zA-Z][a-zA-Z ]*"
if you want it for IOS then,
NSString *yourstring = #"hello";
NSString *Regex = #"[a-zA-Z][a-zA-Z ]*";
NSPredicate *TestResult = [NSPredicate predicateWithFormat:#"SELF MATCHES %#",Regex];
if ([TestResult evaluateWithObject:yourstring] == true)
{
// validation passed
}
else
{
// invalid name
}

Regex pattern for matching only alphabets and white spaces:
String regexUserName = "^[A-Za-z\\s]+$";

Accept only character with space :-
if (!(Pattern.matches("^[\\p{L} .'-]+$", name.getText()))) {
JOptionPane.showMessageDialog(null, "Please enter a valid character", "Error", JOptionPane.ERROR_MESSAGE);
name.setFocusable(true);
}

My personal choice is:
^\p{L}+[\p{L}\p{Pd}\p{Zs}']*\p{L}+$|^\p{L}+$, Where:
^\p{L}+ - It should start with 1 or more letters.
[\p{Pd}\p{Zs}'\p{L}]* - It can have letters, space character (including invisible), dash or hyphen characters and ' in any order 0 or more times.
\p{L}+$ - It should finish with 1 or more letters.
|^\p{L}+$ - Or it just should contain 1 or more letters (It is done to support single letter names).
Support for dots (full stops) was dropped, as in British English it can be dropped in Mr or Mrs, for example.

To validate for only letters and spaces, try this
String name1_exp = "^[a-zA-Z]+[\-'\s]?[a-zA-Z ]+$";

Validates such values as:
"", "FIR", "FIR ", "FIR LAST"
/^[A-z]*$|^[A-z]+\s[A-z]*$/

check this out.
String name validation only accept alphabets and spaces
public static boolean validateLetters(String txt) {
String regx = "^[a-zA-Z\\s]+$";
Pattern pattern = Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(txt);
return matcher.find();
}

To support language like Hindi which can contain /p{Mark} as well in between language characters.
My solution is ^[\p{L}\p{M}]+([\p{L}\p{Pd}\p{Zs}'.]*[\p{L}\p{M}])+$|^[\p{L}\p{M}]+$
You can find all the test cases for this here
https://regex101.com/r/3XPOea/1/tests

#amal. This code will match your requirement. Only letter and space in between will be allow, no number. The text begin with any letter and could have space in between only. "^" denotes the beginning of the line and "$" denotes end of the line.
public static boolean validateLetters(String txt) {
String regx = "^[a-zA-Z ]+$";
Pattern pattern = Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(txt);
return matcher.find();
}

Try with this:
public static boolean userNameValidation(String name){
return name.matches("(?i)(^[a-z])((?![? .,'-]$)[ .]?[a-z]){3,24}$");
}

For Java, you can use below for Name validation which uses Alpha (Letters) + Spaces (Blanks or tabs)
"[^\\\p{Alpha}\\\p{Blank}]"
Can get a reference from Wikipedia for ASCII values also.

Related

Matching three or more identical characters - Java program [duplicate]

I have this small piece of code
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]"))
{
System.out.println(s);
}
}
Supposed to print
dkoe
but it prints nothing!!
Welcome to Java's misnamed .matches() method... It tries and matches ALL the input. Unfortunately, other languages have followed suit :(
If you want to see if the regex matches an input text, use a Pattern, a Matcher and the .find() method of the matcher:
Pattern p = Pattern.compile("[a-z]");
Matcher m = p.matcher(inputstring);
if (m.find())
// match
If what you want is indeed to see if an input only has lowercase letters, you can use .matches(), but you need to match one or more characters: append a + to your character class, as in [a-z]+. Or use ^[a-z]+$ and .find().
[a-z] matches a single char between a and z. So, if your string was just "d", for example, then it would have matched and been printed out.
You need to change your regex to [a-z]+ to match one or more chars.
String.matches returns whether the whole string matches the regex, not just any substring.
java's implementation of regexes try to match the whole string
that's different from perl regexes, which try to find a matching part
if you want to find a string with nothing but lower case characters, use the pattern [a-z]+
if you want to find a string containing at least one lower case character, use the pattern .*[a-z].*
Used
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]+"))
{
System.out.println(s);
}
}
I have faced the same problem once:
Pattern ptr = Pattern.compile("^[a-zA-Z][\\']?[a-zA-Z\\s]+$");
The above failed!
Pattern ptr = Pattern.compile("(^[a-zA-Z][\\']?[a-zA-Z\\s]+$)");
The above worked with pattern within ( and ).
Your regular expression [a-z] doesn't match dkoe since it only matches Strings of lenght 1. Use something like [a-z]+.
you must put at least a capture () in the pattern to match, and correct pattern like this:
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("(^[a-z]+$)"))
{
System.out.println(s);
}
}
You can make your pattern case insensitive by doing:
Pattern p = Pattern.compile("[a-z]+", Pattern.CASE_INSENSITIVE);

How to replace second occurence of pattern in Java? [duplicate]

I have this small piece of code
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]"))
{
System.out.println(s);
}
}
Supposed to print
dkoe
but it prints nothing!!
Welcome to Java's misnamed .matches() method... It tries and matches ALL the input. Unfortunately, other languages have followed suit :(
If you want to see if the regex matches an input text, use a Pattern, a Matcher and the .find() method of the matcher:
Pattern p = Pattern.compile("[a-z]");
Matcher m = p.matcher(inputstring);
if (m.find())
// match
If what you want is indeed to see if an input only has lowercase letters, you can use .matches(), but you need to match one or more characters: append a + to your character class, as in [a-z]+. Or use ^[a-z]+$ and .find().
[a-z] matches a single char between a and z. So, if your string was just "d", for example, then it would have matched and been printed out.
You need to change your regex to [a-z]+ to match one or more chars.
String.matches returns whether the whole string matches the regex, not just any substring.
java's implementation of regexes try to match the whole string
that's different from perl regexes, which try to find a matching part
if you want to find a string with nothing but lower case characters, use the pattern [a-z]+
if you want to find a string containing at least one lower case character, use the pattern .*[a-z].*
Used
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]+"))
{
System.out.println(s);
}
}
I have faced the same problem once:
Pattern ptr = Pattern.compile("^[a-zA-Z][\\']?[a-zA-Z\\s]+$");
The above failed!
Pattern ptr = Pattern.compile("(^[a-zA-Z][\\']?[a-zA-Z\\s]+$)");
The above worked with pattern within ( and ).
Your regular expression [a-z] doesn't match dkoe since it only matches Strings of lenght 1. Use something like [a-z]+.
you must put at least a capture () in the pattern to match, and correct pattern like this:
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("(^[a-z]+$)"))
{
System.out.println(s);
}
}
You can make your pattern case insensitive by doing:
Pattern p = Pattern.compile("[a-z]+", Pattern.CASE_INSENSITIVE);

java regular expression matching with arithmetic operation [duplicate]

I have this small piece of code
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]"))
{
System.out.println(s);
}
}
Supposed to print
dkoe
but it prints nothing!!
Welcome to Java's misnamed .matches() method... It tries and matches ALL the input. Unfortunately, other languages have followed suit :(
If you want to see if the regex matches an input text, use a Pattern, a Matcher and the .find() method of the matcher:
Pattern p = Pattern.compile("[a-z]");
Matcher m = p.matcher(inputstring);
if (m.find())
// match
If what you want is indeed to see if an input only has lowercase letters, you can use .matches(), but you need to match one or more characters: append a + to your character class, as in [a-z]+. Or use ^[a-z]+$ and .find().
[a-z] matches a single char between a and z. So, if your string was just "d", for example, then it would have matched and been printed out.
You need to change your regex to [a-z]+ to match one or more chars.
String.matches returns whether the whole string matches the regex, not just any substring.
java's implementation of regexes try to match the whole string
that's different from perl regexes, which try to find a matching part
if you want to find a string with nothing but lower case characters, use the pattern [a-z]+
if you want to find a string containing at least one lower case character, use the pattern .*[a-z].*
Used
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]+"))
{
System.out.println(s);
}
}
I have faced the same problem once:
Pattern ptr = Pattern.compile("^[a-zA-Z][\\']?[a-zA-Z\\s]+$");
The above failed!
Pattern ptr = Pattern.compile("(^[a-zA-Z][\\']?[a-zA-Z\\s]+$)");
The above worked with pattern within ( and ).
Your regular expression [a-z] doesn't match dkoe since it only matches Strings of lenght 1. Use something like [a-z]+.
you must put at least a capture () in the pattern to match, and correct pattern like this:
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("(^[a-z]+$)"))
{
System.out.println(s);
}
}
You can make your pattern case insensitive by doing:
Pattern p = Pattern.compile("[a-z]+", Pattern.CASE_INSENSITIVE);

Regex with single letter is not identifying

I have a Regex
[\w\W][^\s]+
My intension is to identify a word
may contain special character only
may contain word only
may contain special character and word
can have single letter.
Should not identify space or tab
Above 3 conditions are working, but my 4th condition is not working. Can anyone please help?
[^\s]+
This should do it for you.
\s match any white space character [\r\n\t\f ]
You can use a negated class that allows any 1 or more characters other than a tab or space:
[^\t\p{Zs}]+
See IDEONE Demo:
String str = "Your string here";
String rx = "[^\t\\p{Zs}]+";
Pattern ptrn = Pattern.compile(rx);
Matcher m = ptrn.matcher(str);
while (m.find()) {
System.out.println(m.group(0));
}
You only use [^\s\t\n]+ it identify all single char to many char without (\s=space, \t=tab, \n=enter key)

Regex doesn't work in String.matches()

I have this small piece of code
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]"))
{
System.out.println(s);
}
}
Supposed to print
dkoe
but it prints nothing!!
Welcome to Java's misnamed .matches() method... It tries and matches ALL the input. Unfortunately, other languages have followed suit :(
If you want to see if the regex matches an input text, use a Pattern, a Matcher and the .find() method of the matcher:
Pattern p = Pattern.compile("[a-z]");
Matcher m = p.matcher(inputstring);
if (m.find())
// match
If what you want is indeed to see if an input only has lowercase letters, you can use .matches(), but you need to match one or more characters: append a + to your character class, as in [a-z]+. Or use ^[a-z]+$ and .find().
[a-z] matches a single char between a and z. So, if your string was just "d", for example, then it would have matched and been printed out.
You need to change your regex to [a-z]+ to match one or more chars.
String.matches returns whether the whole string matches the regex, not just any substring.
java's implementation of regexes try to match the whole string
that's different from perl regexes, which try to find a matching part
if you want to find a string with nothing but lower case characters, use the pattern [a-z]+
if you want to find a string containing at least one lower case character, use the pattern .*[a-z].*
Used
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("[a-z]+"))
{
System.out.println(s);
}
}
I have faced the same problem once:
Pattern ptr = Pattern.compile("^[a-zA-Z][\\']?[a-zA-Z\\s]+$");
The above failed!
Pattern ptr = Pattern.compile("(^[a-zA-Z][\\']?[a-zA-Z\\s]+$)");
The above worked with pattern within ( and ).
Your regular expression [a-z] doesn't match dkoe since it only matches Strings of lenght 1. Use something like [a-z]+.
you must put at least a capture () in the pattern to match, and correct pattern like this:
String[] words = {"{apf","hum_","dkoe","12f"};
for(String s:words)
{
if(s.matches("(^[a-z]+$)"))
{
System.out.println(s);
}
}
You can make your pattern case insensitive by doing:
Pattern p = Pattern.compile("[a-z]+", Pattern.CASE_INSENSITIVE);

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