Loops

With in if Statement

Break: 跳出当前判定，以及判断语句上1层 for / while loop

Continue: 跳出当前判定, 所以不执行 当前判断内剩下的命令，但是继续判断语句上1层 loop循环

Pass: 不操作，继续循环，并执行当前判断内剩下的命令

# loop over Dictionary

# Dict can NOT be sorted directly, have to change to list/tuple via .items() for example

vlans = {

"100": {"description": "floor_1", "ip":"192.168.10.1"},

"200": {"description": "floor_2", "ip":"192.168.20.1"},

"300": {"description": "floor_3", "ip":"192.168.30.1"}

}

1. loop through keys only

for i in vlans.keys():

print (i)

100

300

200

2. loop through values only

for k in vlans.values():

print (k['description'])

floor_1

floor_3

floor_2

3. loop through key and values (sorted)

for i, k in sorted(vlans.items()):

print ("vlan ", i)

print ("name ", k['description'])

vlan 300

name floor_3

vlan 100

name floor_1

vlan 200

name floor_2

4. loop in order of Dict key

for key in sorted(vlans.keys()):

print("%s: %s" % (key, vlans[key]))

100: {'ip': '192.168.10.1', 'description': 'floor_1'}

200: {'ip': '192.168.20.1', 'description': 'floor_2'}

300: {'ip': '192.168.30.1', 'description': 'floor_3'}

5. loop in order of Dict value

vlans = {"a": 1001, "b": 2, "c": 30}

print (vlans.items())

dict_items([('c', 30), ('b', 2), ('a', 1001)])

for key, value in sorted(vlans.items(), key=lambda v: v[1]):

print("%s: %s," % (key, value))

b: 2,

c: 30,

a: 1001,