摘要：數(shù)字整型與浮點(diǎn)型整數(shù)沒(méi)有之分浮點(diǎn)數(shù)里面沒(méi)有單精度和雙精度之分表示整除進(jìn)制進(jìn)制，進(jìn)制，進(jìn)制，進(jìn)制，，，。。。。
Number：數(shù)字
1）整型與浮點(diǎn)型
整數(shù)：int（沒(méi)有short、int、long之分）
浮點(diǎn)數(shù)：float（python里面沒(méi)有單精度和雙精度之分）
>>> print("hello world")
hello world
>>> 1
1
>>> 133434
133434
>>> type(1)
>>> type(-1)
>>> type(1.1)
>>> type(1.111111111111111111)
>>> type(1+0.1)
>>> type(1+1)
>>> type(1+1.0)
>>> type(1*1)
>>> type(1*1.0)
>>> type(2/2)
>>> type(2//2)
>>> 2/2
1.0
>>> 2//2
1
>>> 1//2 //表示整除
0
2）10、2、8、16進(jìn)制
>>> 10進(jìn)制，2進(jìn)制，8進(jìn)制，16進(jìn)制
SyntaxError: invalid character in identifier
>>> 0，1，2，3。。。。9，10
SyntaxError: invalid character in identifier
>>> 0，1，10
SyntaxError: invalid character in identifier
>>> 0，1。。。。7，10
SyntaxError: invalid character in identifier
>>> 0，1，2.。。。。。。。9，A,B,C,D,E,F
SyntaxError: invalid character in identifier
表示方法：
二進(jìn)制（0b10）
八進(jìn)制（0o10）
十六進(jìn)制（0x10）
>>> 0b10
2
>>> 0b11
3
>>> 0o10
8
>>> 0o11
9
>>> 0x10
16
>>> 0x11
17
進(jìn)制轉(zhuǎn)換
轉(zhuǎn)換為二進(jìn)制
>>> bin(10)
"0b1010"
>>> bin(0o7)
"0b111"
>>> bin(0xE)
"0b1110"
轉(zhuǎn)換為十進(jìn)制
>>> int(0b111)
7
>>> int(0o77)
63
轉(zhuǎn)換為十六進(jìn)制
>>> hex(888)
"0x378"
>>> hex(0o7777)
"0xfff"
轉(zhuǎn)換為八進(jìn)制
>>> oct(0b111)
"0o7"
>>> oct(0x777)
"0o3567"
3）bool 布爾類(lèi)型(數(shù)字類(lèi)型的一種)：表示真、假
>>> True
True
>>> False
False
>>> true
Traceback (most recent call last):
File "", line 1, in
true
NameError: name "true" is not defined
>>> false
Traceback (most recent call last):
File "", line 1, in
false
NameError: name "false" is not defined
>>> type(True)
>>> type(False)
>>> int(True)
1
>>> int(False)
0
>>> bool(1)
True
>>> bool(0)
False
>>> bool(2)
True
>>> bool(-1.1)
True
>>> bool(0b01)
True
>>> bool(0b0)
False
>>> bool("abc")
True
>>> bool("")
False
>>> bool([1,2,3])
True
>>> bool([])
False
>>> bool({1,1,1})
True
>>> bool({})
False
>>> bool(None)
False
4）complex 復(fù)數(shù)
>>> 36j
36j
str 字符串
1）單引號(hào)
>>> "hello world"
"hello world"
>>> "let"s go"
"let"s go"
2）雙引號(hào)
>>> "hello world"
"hello world"
>>> "let"s go"
SyntaxError: invalid syntax
>>> "let"s go"
"let"s go"
3）三引號(hào)(多行字符串)
>>> """
hello world
hello world
hello world
"""
"
hello world
hello world
hello world
"
>>> """
hello world
hello world
hello world
"""
"
hello world
hello world
hello world
"
>>> """hello world
hello world
hello world"""
"hello world
hello world
hello world"
>>> print("""hello world
hello world
hello world""")
hello world
hello world
hello world
>>> print("""hello world
hello world
hello world""")
hello world
hello world
hello world
>>> print("hello world
hello world
hello world")
hello world
hello world
hello world
>>> """hello world
hello world"""
"hello world
hello world"
>>> "hello
SyntaxError: EOL while scanning string literal
>>> "hello
world"
"helloworld"
4）轉(zhuǎn)義字符（特殊的字符）
無(wú)法“看見(jiàn)”的字符
與語(yǔ)言本身語(yǔ)法有沖突的字符
n 換行
" 單引號(hào)
t 橫向制表符
n 換行
r 回車(chē)
>>> print("hello
world")
hello
world
>>> print(""hello
world"")
"hello
world"
>>> print(""hello
world"")
"hello
world"
>>> print("hello
world")
hello
world
>>> print("c:
orthwind
orthwest")
c:
orthwind
orthwest
>>> print("c:
orthwind
orthwest")
c:
orthwind
orthwest
>>> print(r"c:
orthwind
orthwest")
c:
orthwind
orthwest
>>> r"C:Windows"
"C:Windows"
>>> R"C:Windows"
"C:Windows"
//字符串前加上“r”以后就不是一個(gè)普通字符串，而是一個(gè)原始字符串
>>> print(r" let "s go")
SyntaxError: invalid syntax
//這里的單引號(hào)不是成對(duì)出現(xiàn)，已經(jīng)不是一個(gè)字符串，加上“r”也不會(huì)是原始字符串
字符串運(yùn)算 一
>>> "hello"
"hello"
>>> "world"
"world"
>>> "hello world"
"hello world"
>>> "hello"+"world"
"helloworld"
>>> "hello"*3
"hellohellohello"
>>> "hello" * "world"
Traceback (most recent call last):
File "", line 1, in
"hello" * "world"
TypeError: can"t multiply sequence by non-int of type "str"
>>> "hello world"[0]
"h"
>>> "hello world"[3]
"l"
>>> "hello world"[4]
"o"
>>> "hello world"[5]
" "
>>> "hello world"[-1]
"d"
>>> "hello world"[-3]
"r"
//[-n]表示從字符串的末尾往前數(shù)n次得到的字符
字符串運(yùn)算 二
>>> "hello world"[6]
"w"
>>> "hello world"[-5]
"w"
>>> "hello world"[0:4]
"hell"
>>> "hello world"[0:5]
"hello"
>>> "hello world"[0:-1]
"hello worl"
//這里的-1表示步長(zhǎng)
>>> "hello world"[0:-3]
"hello wo"
字符串運(yùn)算 三
>>> "hello world"[6:10]
"worl"
>>> "hello world"[6:11]
"world"
>>> "hello world"[6:20]
"world"
>>> "hello world"[6:-1]
"worl"
>>> "hello world"[6:0]
""
>>> "hello world"[6:-0]
""
>>> "hello world"[6:]
"world"
>>> "hello python java c# javascript php ruby"[6:]
"python java c# javascript php ruby"
>>> "hello python java c# javascript php ruby"[:-4]
"hello python java c# javascript php "
>>> "hello python java c# javascript php ruby"[0:-4]
"hello python java c# javascript php "
>>> "hello python java c# javascript php ruby"[-4:]
"ruby"
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