Python flow control statement structure summary

if conditional statement
 if <test1>: can be nested
    <statements1>
elif <test2>: can be omitted
    <statements2>
else : Optional: Optional
    <statements3>

The ternary expression 
A=Y if X else Z executes expression Y when X is true, and executes expression Z when X is false
Equivalent to
A=X and Y or Z

while循环
while <test>：
    <statements1>
else : Optional: Optional
    <statements2>

for循环
for <target> in <object>:
    <statements>
else : Optional: Optional
    <statements>

break : jump out of the most recent loop
 continue : jump to the beginning of the most recent loop and execute the next loop
 pass : do nothing, just an empty station statement, can also be used after python3.0 ... instead
The loop else is fast: it will only be executed when the loop leaves normally (that is, no break statement is encountered)