Re-learning Python-day 03-python Basic And while loop instance + Continue && Break application + List of initial learning

application of the while statement

Examples are as follows:

1 """2 User Login system, can only log in at most three times3 after the third failure, the program terminates4 5 """6User_table = {"python":"Important","Java":"more_important","Shell":"Linux"}7Time = 18 9  whileTime < 4:Tenuser_name = input ("Please enter your user name:") OneUser_password = input ("Please enter your password:") A     ifUser_nameinchUser_table.keys () andUser_passwordinchUser_table.values ():#very low, because the user name and password can be mixed, and later update it -         Print("welcome,master!! ") -          Break the     Else: -         Print("You failed login system!!") -         ifTime = = 3: -             Print("Three chances is all userd!!") +Time + = 1

Ps:1. The results of the run do not show

2. I choose the IDE is pycharm, registration code own Baidu keyword: pycharm 2017 registration Code (self-study can be used, but to the regular company Don't Mess with)

Understanding and examples of continue and break statements

Continue: The current cycle jumps out and continues the next loop

Break: Jump out of the current entire loop

1Flag =False2  forIinchRange (10):3     ifI < 6:4         Continue  #0 to 5 is skipped, the print statement behind it cannot be executed5     Print(i)#When i = 6, start printing6      forJinchRange (10):7         Print(j)8         ifj = = 5:9Flag =TrueTen              Break  #interrupts the current loop, and the second for loop is interrupted One     #If flag: A     #break cancels the comments on both lines, the first for loop is interrupted and can be judged according to the format

Python Classic data Type--list

Example:

1List1 = ["a","b","C","e","F","D"]2 3 Print(List1[3])#the first index, not the left or right, is the default index value from the left, and the following index example is4 Print(list1[1:])#The first value to the last value5 Print(List1[1:-1])#-1 is the second-lowest value6 Print(List1[::-1])#The list is reversed. -1 means go from right to left7 Print(list1[4::-1])8 Print(List1)9 Ten  One #List Modification AList1.append ("python") - Print(List1) -  the #to modify a value at a specified location -LIST1[2] ="Java" - Print(List1) -  + #Insert -List1.insert (1,"Ruby") + Print(List1) A  at #Remove a method remove del pop -List1.remove ("Java")#You can also specify a value with an index, List1.remove (list[1]) - Print(List1) -List1.pop (2) - Print(List1) - delList1[1] in Print(List1)

Operation Result:

e['b','C','e','F','D']['b','C','e','F']['D','F','e','C','b','a']['F','e','C','b','a']['a','b','C','e','F','D']['a','b','C','e','F','D','python']['a','b','Java','e','F','D','python']['a','Ruby','b','Java','e','F','D','python']['a','Ruby','b','e','F','D','python']['a','Ruby','e','F','D','python']['a','e','F','D','python'] The process has ended, exit code 0

PS: List of built-in functions put on tomorrow's notes

Re-learning Python-day 03-python Basic And while loop instance + Continue && Break application + List of initial learning