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Limit number of characters allowed in form input text field
How do I limit or restrict the user to only enter a maximum of five characters in the textbox?
13 Answers
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How to limit the maximum value of a numeric field in a Django model?
...
Here is the best solution if you want some extra flexibility and don't want to change your model field. Just add this custom validator:
#Imports
from django.core.exceptions import ValidationError
class validate_range_or_null(object):
compare = lambda self,...
Highlight text similar to grep, but don't filter out text [duplicate]
...e the regex engine notices the empty alternation at the end of the pattern string matches the beginning of the subject string.
[1]: http://www.regular-expressions.info/engine.html
FIRST EDIT:
I ended up using perl:
perl -pe 's:pattern:\033[31;1m$&\033[30;0m:g'
This assumes you have an ANS...
Favorite (Clever) Defensive Programming Best Practices [closed]
...
When printing out error messages with a string (particularly one which depends on user input), I always use single quotes ''. For example:
FILE *fp = fopen(filename, "r");
if(fp == NULL) {
fprintf(stderr, "ERROR: Could not open file %s\n", filename);
retu...
How to remove from a map while iterating it?
...r this pattern which is slightly clearer and simpler, at the expense of an extra variable:
for (auto it = m.cbegin(), next_it = it; it != m.cend(); it = next_it)
{
++next_it;
if (must_delete)
{
m.erase(it);
}
}
Advantages of this approach:
the for loop incrementor makes sense as an ...
How to add anything in through jquery/javascript?
...
You can use innerHTML to just concat the extra field string;
document.head.innerHTML = document.head.innerHTML + '<link rel="stylesheet>...'
However, you can't guarantee that the extra things you add to the head will be recognised by the browser after the first load, a...
How to pass arguments to a Button command in Tkinter?
...ss', command=fce)
See: http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/extra-args.html
For more buttons you can create a function which returns a function:
def fce(myX, myY):
def wrapper(x=myX, y=myY):
pass
pass
pass
return x+y
return wrapper
button1 = ...
Catch a thread's exception in the caller thread in Python
...rns to the main thread immediately when an exception is called
requires no extra user defined classes because it does not need:
an explicit Queue
to add an except else around your work thread
Source:
#!/usr/bin/env python3
import concurrent.futures
import time
def func_that_raises(do_raise)...
Maven Install on Mac OS X
...
Download Maven from its homepage
Follow the installation instructions:
Extract the distribution archive, i.e.apache-maven-3.3.9-bin.tar.gz to the directory you wish to install Maven 3.3.9. The subdirectory apache-maven-3.3.9 will be created from the archive.
Optional: Add the MAVEN_OPTS environm...
Java: Subpackage visibility?
...sInA in package a.b:
package a;
public class ClassInA{
private final String data;
public ClassInA(String data){ this.data = data; }
public String getData(){ return data; }
protected byte[] getDataAsBytes(){ return data.getBytes(); }
protected char[] getDataAsChars(){ return...