Python快速上手之流程控制語法（day2）

python流程控制語法

if語句

var1 = 100

if var1:
print "1 - got a true expression value"
print var1
var2 = 0
if var2:
print "2 - got a true expression value"
print var2
print "good bye!"

#如果是數字，則只要不等於0，就為true

#如果是字串，則只要不是空串，就為true

if else

var = 100

if var == 200:
print "1 - got a true expression value"
print var
elif var == 150:
print "2 - got a true expression value"
print var
elif var == 100:
print "3 - got a true expression value"
print var
else:
print "4 - got a false expression value"
print var
print "good bye!"

var = 100

if var < 200:
print "expression value is less than 200"
if var == 150:
print "which is 150"
elif var == 100:
print "which is 100"
elif var == 50:
print "which is 50"
elif var < 50:
print "expression value is less than 50"
else:
print "could not find true expression"
print "good bye!"

count = 0

while count < 5:
print count, " is  less than 5"
count = count + 1
else:
print count, " is not less than 5"
x=2i=0
while x<34:
i+=1
if i==12:
print "break....................................."
break
;    print x
x=35
i=0while x<34:
i+=1
if i==12:
print "break....................................."
break
;    print x
else:
print "沒有執行迴圈......."

for i in range(0,5):

print i;
for i in range(0,5,1):
print i;
for i in range(5,0,-1):
print i;

r=range(10,20)

r=#set型別r=[
"aaa",3,"c"
]print(r)
for num in r:
print(num)
r=print(r)
for num in r.values(
):    print(num)

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