import timeit

s = 'd = dict(a=3, b=5)'

s1 = """\
try:
    d['a']
except KeyError:
    pass
"""

s2 = """\
if 'a' in d:
    d['a']
"""
print('always hit')
print('try:', timeit.Timer(s1, s).timeit())
print('in :', timeit.Timer(s2, s).timeit())



s1 = """\
try:
    d['c']
except KeyError:
    pass
"""

s2 = """\
if 'c' in d:
    d['c']
"""
print('always miss')
print('try:', timeit.Timer(s1, s).timeit())
print('in :', timeit.Timer(s2, s).timeit())



s1 = """\
for k in 'ababaccccc':
    try:
        d[k]
    except KeyError:
        pass
"""

s2 = """\
for k in 'ababaccccc':
    if k in d:
        d[k]
"""
print('5 hit, 5 miss')
print('try:', timeit.Timer(s1, s).timeit())
print('in :', timeit.Timer(s2, s).timeit())



s1 = """\
for k in 'ababababac':
    try:
        d[k]
    except KeyError:
        pass
"""

s2 = """\
for k in 'ababababac':
    if k in d:
        d[k]
"""
print('9 hit, 1 miss')
print('try:', timeit.Timer(s1, s).timeit())
print('in :', timeit.Timer(s2, s).timeit())