Python Basics 4 (looping and commenting)

(1) while loop

#当某个条件成立时, always perform an action with the following syntax:

while conditional expression:
Loop code

#条件表达式结果为True的时候 Loop code is always executed
#知道条件表达式结果为False

while True:
　　if (input(' input is a? ') = =' A '):
　　　　Break
Note: The above code is a dead loop, and the program is terminated only when you enter a.

#简单打印出1到100数字

Cur= 1
whileCur<= -:
　　 Print(cur)
Cur += 1

#打印所有学生信息 [' Mike ', ' Jack ', ' Luoqian ', ' Chenzi ', ' Liqian ']
ARR1 = [' MikE ',' Jack ',' Luoqian ',' Chenzi ', ' Liqian ']
I=0
whileI< Len(ARR1):
　　 Print(Arr1[i])
i +=1

（2） forCycle

#打印所有学生信息 [' Mike ', ' Jack ', ' Luoqian ', ' Chenzi ', ' Liqian ']
arr1 = [' Mike ',' Jack ', 'Luoqian ',' Chenzi ',' Liqian ']
for Stu in arr1:
　　Print (Stu) #stu就代表列表中的元素

Note: The above two examples show that the while loop requires a variable, which requires a self-increment of 1.

Add: Python2 range xrange The difference between the two
The #range function returns a list, and xrange is like a generator
#如果需要遍历一个很庞大的数字范围, with Xrange, because it saves memory
Range in #Python3 similar to xrange in Python2

for stu in range (1 , 101 , 10 ):
# package left not packet right, take 1 to 100, followed by 10 is the number of steps, that is, every 10 digits print once
#打印结果为: 1,11, ...
print (stu)

Note: If the number of steps is negative
for stu in range ( 101 , 1 , -10 ):
#打印结果为: 101, he, Bayi, ...
print (Stu)

(3 ) break statement: This layer loops over the specified condition and no longer loops back, if there are other outer or inner loops that do not affect

Sumdata = 0
for i in range(1, 101):
Sumdata += I
　　if i = = :
　　　　 Break #结束本层循环
Print (Sumdata)

(4) contiune statement: The end of the cycle, after the next cycle, if there are other outer or inner loop does not affect

(5) Notes
#注释方法一: Use "#"

#注释方法二: Multiple lines of comment with three quotation marks ""

#注释方法三: Comment for function

def Fun ():
　　#函数的属性
　　"This is Doc"
　Print ("Function! ")
Print (fun.__doc__)

#打印后会显示里面的 the "This is Doc" property explains

Python Basics 4 (looping and commenting)