Loop Exit
For loop:
For
Else
The For loop will execute the ELSE statement if it ends normally.
Script 1:
#!/usr/bin/env python
for I in Xrange (10):
Print I
Else:
Print "Main End"
Results:
[email protected] 20171227]# python exit.py
0
1
2
3
4
5
6
7
8
9
Main end
[Email protected] 20171227]#
Script 2:
#!/usr/bin/env python
Import time
For I in Xrange (10):
Print I
Time.sleep (1)
Else
Print "Main End"
Result: (Press CTRL + C interrupt)
[email protected] 20171227]# python exit.py
0
1
2
3
4
^ctraceback (most recent):
File "exit.py", line 6, <module>
Time.sleep (1)
Keyboardinterrupt
[Email protected] 20171227]#
Script 3:
Does not end normally:
#!/usr/bin/env python
Import time
For I in Xrange (10):
Print I
if i = = 5:
Break
Else
Print "Main End"
Results:
[email protected] 20171227]# python exit.py
0
1
2
3
4
5
[Email protected] 20171227]#
Script 4: (skip this cycle continue)
#!/usr/bin/env python
Import time
For I in Xrange (10):
if i = = 3:
Continue
if i = = 5:
Break
Print I
Else
Print "Main End"
Results:
[email protected] 20171227]# python exit.py
0
1
2
4
[Email protected] 20171227]#
Script 5: (Pass does nothing)
#!/usr/bin/env python
Import time
For I in Xrange (10):
if i = = 3:
Continue
elif i = = 5:
Break
Elif I ==6:
Pass #类似shell:
Print I
Else
Print "Main End"
Script 6:
#!/usr/bin/env python
Import time
Import Sys
For I in Xrange (10):
if i = = 3:
Continue
elif i = = 5:
Continue
Elif I ==6:
Pass
Elif I ==7:
sys.exit ()
Print I
Else
Print "Main End"
Print "hahaha"
Results:
[email protected] 20171227]# python exit.py
0
1
2
4
6
[Email protected] 20171227]#
Pip shows a third-party package
[[Email protected] 20171227]# PIP list
Deprecation:the default format would switch to columns in the future. You can use--format= (legacy|columns) (or define a format= (Legacy|columns) in your pip.conf under the [list] sections) to D Isable this warning.
Backports.ssl-match-hostname (3.4.0.2)
Chardet (2.2.1)
Configobj (4.7.2)
Decorator (3.4.0)
Iniparse (0.4)
IPy (0.75)
Ipython (1.2.1)
Jsonschema (2.5.1)
Kitchen (1.1.1)
Langtable (0.0.31)
Matplotlib (1.2.0)
Homework: Guess the number game
The system generates a random integer within 20.
Players have 6 chance to guess, every guess has feedback (guess big, guess small, guess right-end)
6 plays, guessed right, the player won.
Otherwise the system won .
In [1]: Import random
In [2]: Random.ran
Random.randint Random.random Random.randrange
In [2]: Random.randint (1,20)
OUT[2]: 14
In [3]: Random.randint (1,20)
OUT[3]: 6
Process Control-while Example
While and for relative ratio:
The For loop is used on a number of cycles.
The while loop is used for conditional control.
While loop:
The while loop is not exited until the expression becomes false. While loop, the expression is a logical expression and must return a true or false
Grammar:
While expression:
Statement (s)
Practice the script if:
Script 1:
#!/usr/bin/python
n = 0
While 1:
if n = = 10:
Break
Print N, ' Hellow '
N +=1
Results:
[email protected] 20171227]# python while.py
0 Hellow
1 Hellow
2 Hellow
3 Hellow
4 Hellow
5 Hellow
6 Hellow
7 Hellow
8 Hellow
9 Hellow
[Email protected] 20171227]#
Script 2:
#!/usr/bin/python
While 1:
print ' Hellow '
Input=raw_input ("Please input sth,q for exit.")
If input = = "Q":
Break
Results:
[email protected] 20171227]# python while.py
Hellow
Please input sth,q for EXIT.S
Hellow
Please input sth,q for exit.3
Hellow
Please input sth,q for EXIT.Q
[Email protected] 20171227]#
If the condition is false, it will also exit:
Script 3:
#!/usr/bin/python
Sth= "
While sth! = ' Q ':
print ' Hellow '
Sth=raw_input ("Please input sth,q for exit.")
Script 4:
Exit after Enter:
#!/usr/bin/python
Sth= "
While sth! = ' Q ':
print ' Hellow '
Sth=raw_input ("Please input sth,q for exit.")
If not sth:
Break
Script 5:
#!/usr/bin/python
Sth= "
While sth! = ' Q ':
print ' Hellow '
Sth=raw_input ("Please input sth,q for exit.")
If not STH:
Break
Else
print ' World '
Results:
[email protected] 20171227]# python while.py
Hellow
Please input sth,q for EXIT.Q
World
[Email protected] 20171227]#
Script 6:
#!/usr/bin/python
Sth= "
While sth! = ' Q ':
print ' Hellow '
Sth=raw_input ("Please input sth,q for exit.")
If not STH:
Break
if sth = = ' Quit ':
Continue
print ' Continue '
Else
print ' World '
Results:
[email protected] 20171227]# python while.py
Hellow
Please input sth,q for EXIT.SS
Continue
Hellow
Please input sth,q for EXIT.DF
Continue
Hellow
Please input sth,q for exit.quit
Hellow
Please input sth,q for EXIT.Q
Continue
World
Example of a loop exit in Python and a while loop