def physics_people():
names = []
for (name, phone) in phones: # phones is the source
if physics_dept(phone): # physics_deptn(phone) is the filter
names.append(name) # name is the pattern
return names
def physics_people():
names = []
for (name, phone) in phones: # phones is the source
if physics_dept(phone): # physics_deptn(phone) is the filter
names.append(name) # name is the pattern
return names
print phones
# use a loop to build up a list from a source, filter, and pattern:
def physics_people():
names = []
for (name, phone) in phones: # phones is the source
if physics_dept(phone): # physics_deptn(phone) is the filter
names.append(name) # name is the pattern
return names
print physics_people()
# a list comprehension expresses the same thing in one expression
# [ pattern for item in source if filter ]
print [ name for (name, phone) in phones if physics_dept(phone) ]
# the pattern can be elaborate
print [ "%s's phone is %s" % (name,phone)
for (name, phone) in phones if physics_dept(phone) ]
# note the difference between filter and conditional expr. in pattern
def odd(i): return i%2 # 1 (true) when i is odd, 0 (false) when even
print [ (i, 'odd') for i in range(5) if odd(i) ] # filter
print [ (i, 'odd' if odd(i) else 'even') for i in range(5) ] # pattern
# use a loop to build up a list from a source, filter, and pattern:
def physics_people():
names = []
for (name, phone) in phones: # phones is the source
if physics_dept(phone): # physics_deptn(phone) is the filter
names.append(name) # name is the pattern
return names
print physics_people()
# a list comprehension expresses the same thing in one expression
# [ pattern for item in source if filter ]
print[name for (name, phone) in phones if physics_dept(phone)]
# the pattern can be elaborate
print[
"%s's phone is %s" % (name, phone) for (name, phone) in phones
if physics_dept(phone)
]
# note the difference between filter and conditional expr. in pattern
def odd(i):
return i % 2 # 1 (true) when i is odd, 0 (false) when even
print[(i, 'odd') for i in range(5) if odd(i)] # filter
