A user interaction:
···· input () function of the input
···· output () function output
# A = ( "Please enter your name") print ( "This man's name is" + a) = the person's name is XXX
# A = ( "any number") b = ( "another arbitrary number") If the input 1 and 2
print (a + b) = 12 because the data type is string received
c = int (a) d = int (b) print (c + d) = 3 calculates the data type needs to be first converted into an integer data type int then calculated.
Second flow control if statement: if elif else
if condition is determined:
Implementation condition is true, executing the current code block.
elif
The condition is false, continue to judge below.
else：
Condition is false, the above code block is not executed, executing the current code block.
'''
money = 1000
if money > 5000:
print ( "car")
elif money > 3000:
print ( "buy bicycle")
elif money > 1000:
print ( "shoes")
else：
print ( "do not buy")
Three nesting Note: Indent (Tab)
'''
P = input ( "You are men and woman?")
if P == "female" # == judgment, can only be a woman
age = input ( "How old?")
if int (age)> 30: #age age, type integer
print ( "off")
else：
print ( "Come")
else：
print ( "Go away")
'' '# Note indent
# In development, so as not more than three levels of nesting. if and else can be nested.