Python for Bioinformatics: NSPredicate: PyObjC version

Sunday, March 13, 2011

NSPredicate: PyObjC version

Here is the answer in the previous post, converted to PyObjC. It's a bit simpler, except that some of the methods require a "real" NSArray or NSString.

from Foundation import *
import objc

class NSString(objc.Category(NSString)):
    def validate(self):
        A = self.UTF8String().split(':')
        fm = NSFileManager.defaultManager()
        def f(s):
            print 'test', s
            home = NSHomeDirectory()
            s = s.replace('~',home)
            return fm.fileExistsAtPath_(s)
        return all([f(s) for s in A])
        
s = NSString.stringWithString_('~/Desktop')
print s.validate()

for s in ['~:~/Desktop','xyz']:
    s = NSString.stringWithString_(s)
    f = NSExpression.expressionForConstantValue_(s)
    e = NSExpression.expressionForFunction_selectorName_arguments_(
            f,'validate',None)
    results = e.expressionValueWithObject_context_(None,None)
    print results
print

p = NSPredicate.predicateWithFormat_(
        "FUNCTION(SELF, 'validate') isEqual:YES")
A = ['~/Desktop','xyz']
A = [NSString.stringWithString_(s) for s in A]
A = NSArray.arrayWithArray_(A)
for item in A.filteredArrayUsingPredicate_(p):
    print item

print p.evaluateWithObject_(NSString.stringWithString_('~/Desktop'))

output:

test ~/Desktop
True
test ~
test ~/Desktop
True
test xyz
False

test ~/Desktop
test xyz
~/Desktop
test ~/Desktop
True