1. The user interaction
input (prompt) will return to what you type
input string is accepted content
name = input ( "Please enter your name:") # the program will stop here, waiting for user input
s = "My name is" + name + ", this year 18-year-old" string #name string
print(s)
print (1+ "ha ha") does not want to add the correct print ( "1" + "ha ha")
a = input ( "Enter a:")
b = input ( "Enter b:")
print(a+b)→1020(a=10,b=20)
# String into int
#int(str)
c=int(a)
d = int (b) # non-numeric type can not appear
print(a+b)→30
# Constants: Variables can not change, there is no absolute constants in python, everyone convention, all the variables in capital letters is constant
PI=3.1415926
SYLAR_BIRTHDAY=1991
print(PI)
# Print statement
print ( "12", "13") "," output will be a space
a=10
b=20
print("a+b=",a+b)→ a+b= 30
2. conditional -if
Create a new folder if.py
money=300
# If: if
# Money> 500 conditions
#: Start block
# A Blank: tab (indentation) - block (slave and if)
#If stuff out
if money>500
print ( "taxi home")
print ( "home")
Home if money = 800 Ze taxi home home
grammar
if conditions
Block
Description: When the (true) condition is established, the code block is executed
money=800
if money>500：
print ( "drink a little wine")
else: # content table Otherwise, when the condition is not satisfied
print ( "water")
grammar
if conditions:
Block
else：
Block
money=8000
if money>3000:
print ( "big sword")
elif money>2000:
print ( "feet City")
elif money>1000:
print ( "drink a little wine")
else: # will not go
print ( "home water")
grammar
if Condition 1:
Block
elif Condition 2:
Block
Elif ...
else:
When the condition 1 is satisfied, the execution code 1, the condition 1 is not satisfied, it is determined again 2, and so on (which will execute a block of code)
if sex=="女"：
if int(age)<20:
print ( "open the door, how?")
else：
print ( "not open")
print ( "Oh OMG")
else：
print ( "Goodbye")
3. loop --while
New while.py
flag=True
count=1
while flag:
print ( "1 glare")
print ( "what you see")
print ( "see you gnaw")
print("上")
count = count + 1 #count back increment
if count==6：
flag=False
print ( "eat")
If there is no circulation would have been if, Ctrl + c to stop
grammar
while conditions:
Block
Description: determining whether the condition is true, if true, the code block is executed (loop) continue executing the determination condition is true, if true, execution continues until the condition is false, the cycle is stopped
The number of problem number #
index=1
while index<101：
print(index)
index=index+1
1+2+3+4+......+100=?
index=1
sum=0
while index<101:
sum=sum+index
index=index+1
print(sum)
4.break
#break: interrupt cycle, a cycle completely stopped (turning off the current cycle of this layer)
#coutinue: stopped this cycle, the next cycle continues
index=1
while index<101:
print(index)
index=index+1
if index==88
stopped circulating break #
index=1
while index<101:
if index==88: if index！=88:
(Index = index + 1) only 88
continue
print(index)
index=index+1
Without brackets in the content, only to 87