Testing various ways to test a dictionary (say, a wsgi environ) for an AJAX request

test1.py

stmt = """
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
"""

timeit.timeit(stmt=stmt, number=10000000)
# yields 2.7133121490478516

test10.py

stmt = """
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = environ['HTTP_X_REQUESTED_WITH'][0] == 'X'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 3.305811882019043

test11.py

stmt = """
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = len(environ['HTTP_X_REQUESTED_WITH']) == 14
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 3.3983161449432373

test12.py

stmt = """
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = environ['HTTP_X_REQUESTED_WITH'].startswith('X')
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 5.772078037261963

test2.py

stmt = """                               
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
result = environ.get('HTTP_X_REQUESTED_WITH', '') == 'XMLHttpRequest'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 3.8378548622131348

test3.py

stmt = """                               
environ = {}
result = environ.setdefault('HTTP_X_REQUESTED_WITH', '') == 'XMLHttpRequest'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 3.446074962615967

test4.py

stmt = """
environ = {}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'                                                                   
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 1.0769789218902588

test5.py

stmt = """
environ = {
        'HTTP_X_REQUESTED_WITH': 'HttpRequest'
}
if 'HTTP_X_REQUESTED_WITH' in environ:
        result = environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 2.849605083465576

test6.py

stmt = """                               
environ = {}
result = 'HTTP_X_REQUESTED_WITH' in environ and environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 1.4808499813079834

test7.py

stmt = """                               
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
result = 'HTTP_X_REQUESTED_WITH' in environ and environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 2.8417441844940186

test8.py

stmt = """                               
environ = {}
try:
        result = environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
except KeyError:
        result = False
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 15.797735214233398

test9.py

stmt = """                               
environ = {
        'HTTP_X_REQUESTED_WITH': 'XMLHttpRequest'
}
try:
        result = environ['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
except KeyError:
        result = False
"""
timeit.timeit(stmt=stmt, number=10000000)
# yields 2.8694100379943848