浅谈Python基础―判断和循环

判断

缩进代替大括号。

冒号（:）后换号缩进。

test=100
if test>50:
 print('OK')
print('test')

if-elif-else

test=50
if test>200:
 print('200')
elif test<100:
 print('100')
else:
 print('100-200')

列表

test1=[123,456,789]
if 123 in test1:
 print('OK')

字典

test2={'hello':123,'world':456}
if 'hello' in test2:
 print('OK')

循环

while

数值

test=0
while test<10:
 print(test)
 test+=1

集合

test1=set(['hello','world'])
while test1:
 test2=test1.pop()
 print(test2)

for

集合

test3=set(['hello','world'])
for t in test3:#相当于foreach
 print(t)

列表

test4=[123,456,789]
for i in range(3):
 print(test4[i])

test5=[123,456,789,34,5435,26,2362,262,26,5]
for i in range(len(test5)):
 print(test5[i])

continue

test6=[11,12,13,14,15,16,17,18,19,20]
for i in test6:
 if i%2==0:
  print(i) 
 else:
  continue
 print(i)

break

test7=[12,13,14,15,16,17,18,19,20]
for i in test7:
 if i%2==0:
  print(i) 
 else:
  break
 print(i)