Six basic data types

# ! / Usr / bin / to python3 
# Python basic syntax and data types 
# to python3 a plurality of statements in a row, separated by a semicolon (;) 
Print ( " AAA " ); Print ( " BBB " )

# Basic data types, the type of long removed 
Print (type (. 1 ))
 Print (type (1.0 ))
 Print (type ( " STR " ))

# Allows multiple variables continuous assignments
a=b=c=1
print(a,b,c)

a,b,c=1,2,"bb"
print(a,b,c)

# Standard data types 6 kinds 
# Number The (digital) 
# String (String) 
# List (list) 
# Tuple (tuple) 
# Sets (set) 
# of Dict (dictionary)

# Number The (digital) 
# support int float bool complex (complex) 
# numerical 
Print ( " . 5 + =. 3 " ,. 5 +. 3 )
 Print ( " 5-3 = " , 5-3 )
 Print ( " . 5 *. 3 = " ,. 5 * 3 )
 Print ( " divide down float 2 / =. 4 " , 2 /. 4 )
 Print ( " divide down. 4 = integer // 2 " , // 2. 4 )
 Print ( " modulo 3 = 10% " , 10%. 3 )
 Print ( "Power ** 2 = 4 " , 4 ** 2 )
 Print ( " prescribing 0.5 ** = 4 " , 4 * 0.5 )


# String (String) 
# elements are immutable 
String = " ABCDEFG " 
Print (String)
 Print (String [0])
 Print (String [0: -1]) # start to finish 
Print (String [2:]) # from the lower end of the subscript 2 
Print (String [2:. 4]) # from the subscript 2. 1-n-[m, n-) 
Print (String * 2) # output 2


# List (list) 
# variable element 
listDemo = [ " AA " ,. 1, " BB " , 2 ]
 Print (listDemo)
 Print (listDemo [0]) # output index 0 
Print (listDemo [2:]) # starting from index 2 to the tail 
Print (listDemo [. 1:. 3]) # at index 2 to the n--. 1 [m, n-) 
Print (listDemo * 2) # output 2 
listDemo [0] = " alternative " 
Print (listDemo) # amended


# Tuple (a tuple) 
# elements immutable 
tupleDemo = ( " AA " ,. 1, " BB " , 2 )
 Print (tupleDemo) 
 Print (tupleDemo [0]) # output index 0 
Print (tupleDemo [2:]) # 2 start index from the tail 
Print (tupleDemo [. 1:. 3]) # at index 2 to the n--. 1 [m, n-) 
Print (tupleDemo * 2) # output 2 

tupleDemo = () # empty tuple 
tupleDemo = (a,) # an element 
Print (tupleDemo)


# The Set (set) 
# a non-repeating random sequences 
setDemo = { " A " , " B " , " C " }
 Print ( " set A " , setDemo)
 # set may be set intersection and difference set 
setDemo2 = { " a " , " B " }
 Print ( " set B " , setDemo2)
 Print ( " AB of the difference set " , setDemo- setDemo2)
 Print ( "AB union ", setDemo | setDemo2)
 Print ( " AB intersection " , setDemo & setDemo2)
 Print ( " AB does not exist at the same time " , setDemo ^ setDemo2)


#字典
dictDemo={"tom":"90","jerry":"75"}
print(dictDemo)
print(dictDemo["tom"])
print("keys:",dictDemo.keys())
print("values",dictDemo.values())
#移除 key 返回value
print("移除tom ",dictDemo.pop("tom"))
print(dictDemo)


# Python common data conversion 
'' '
int(x)
str(x)
tuple (s) converted into a sequence of tuples
list (s) to convert the sequence listing
'''


# Python Notes 
Print ( " single-line comments # " )
 Print ( " multi-line comment single quotation mark (3 ') " )
 Print ( " multi-line comment double quotation marks (three double quote) " )