The path of Python cultivation-day2

Tag: Precedence equals ESS requires logical statement result while loop%s

A. While loop

Basic usage:

While condition:

　　　　Code Block 1

Else

　　　　Code Block 2

Running process: 1) When the condition is set, execute code block 1

2) again determine if the condition is true, if true, execute code block 1 again ....

3) When the condition is false. Execute else jumps out of the loop. End of cycle

1. Use the while loop to output 1-10 integers

I=1 while i<=10:    print(i)                        

2. Outputs 1-100 of all integers and

I=1=0 while i<=100:    sum=sum+i    i+=1print (i)

3. All odd numbers in the output 1-100

 while Num <=:    if num% 2! = 0:        print(num)    + = 1

4. Guess the number of small games

Count = 3Num=66 whileCount >= 1: Guess= Input ("Please enter a number:")    ifGuess = =Num:Print("guess the result is correct")         Break    elifGuess >Num:Print("guess the result is big.")    Else:        Print("guess the results are small.") Count-= 1Else:    Print("you are so stupid .")

5. Ask for the 1-2+3-4+5....99 of all the numbers.

Start = 1= 0 while start <100:    = start% 2    if temp ==1:        /c7>= sum + start    else:        = Sum- start    + = 1print( Sum

6. Enter a number to determine the number of digits (implemented by the algorithm)

1 count = 12 num = Int (input (" Please enter a number:"))3while  True:4     num = num/105     if num <:6 c16/>Break7         8     count + = 29print(count)

Two. Formatted output

%s: a placeholder for a string that can place any content (number)

%d: placeholder for number

1. Example of a string placeholder

1Name = input ("Please enter your first name:")2Age = Input ("Please enter your age:")3Hobby = input ("Enter your hobby:")4gender = input ("Please enter your gender:")5 6 Print("%s Old this year, is an old man, hobby is%s, gender:%s"% (name, age, hobby, gender))

2. Example of a digital placeholder

A = 108" there are%d characters in Liangshan shui Bo " % (a)print(s)

>>>> Tip: If a placeholder is in the string. Then all the percent behind is a placeholder. need to be escaped;% or%

three. Operators

operations can be divided into: arithmetic Operations , comparison operations , logical Operations , assignment Operations , member operations, identity operations, bit operations.

1. Arithmetic operations

operator : ' + ', '-', ' * ', '/', '% ', '//', ' * * ' (subtraction takes the whole power in order)

2. Comparison operations

　　operator : ' = = ', '! = ', ' <> ', ' > ', ' < ', ' >= ', ' <= ' (equals not equals not equal to less than or equal to less than or greater than or equal to)

3. Assignment operation

　　operator : ' = ', ' + = ', '-= ', ' *= ', '/= ', ' **= ', '//= ', '%= '

4. Logic operation:

　　operator : ' and ', ' or ', ' not '

　　and: and meaning. The values on both sides must be true. The result of the operation is true.

　　or: or meaning. One of the left and right ends is true. The result is true. All is false. The result can be false

　　not: non-meaning. It turns out to be false. It's true now. Not true or false, not false both true

Logical operation Priority: () > Not > and > or

Determine the true,false of the following column logical statement sentences.

3>4or4<3 and1==1 1 < 2 and3 < 4or1>2 2 > 1 and3 < 4or4 > 5 and2 < 1 1 > 2 and3 < 4or4 > 5 and2 > 1or9 < 8 1 > 1 and3 < 4or4 > 5 and2 > 1 and9 > 8or7 < 6 not2 > 1 and3 < 4or4 > 5 and2 > 1 and9 > 8or7 < 6

The >>>> operation results are: false, True, True, False, False, False

The second method of operation :

　　　　　　　x or Y, X is true, value is x,x false, value is y

X and y, X is true, value is y,x false, value is x

Determine the following logical statements

Print(0or1or3or0or5)    Print(1 and2)  Print(2 and0)Print(0 and3)  Print(0 and4)  Print(0or4 and3or7or9 and6)Print(2 > 3 and3)      Print(2 < 1 and4 > 6or3 and4 > 5or6)

The results of the >>>>>>> operation are: 1, 2, 0, 0, 0, 3, 0, 6

Break ends the loop. Stop the current layer loop
Continue ends the current cycle. Proceed to the next loop

The path of Python cultivation-day2