数据类型
您可以使用type（）函数获取任何对象的数据类型。
x = 5
print(type(x))
数字类型
x = 1 # int
y = 2.8 # float
z = 1j # complex
Int，或integer，是一个长度不限的整数，正数或负数，不带小数。
x = 1
y = 35656222554887711
z = -3255522
浮点数，或“浮点数”是一个包含一个或多个小数的正数或负数。
x = 1.10
y = 1.0
z = -35.59
浮点数也可以是科学数字，用“e”表示10的幂。
x = 35e3
y = 12E4
z = -87.7e100
复数是用“j”作为虚部写成的
x = 3+5j
y = 5j
z = -5j
您可以使用int（）、float（）和complex（）方法从一种类型转换为另一种类型
x = 1 # int
y = 2.8 # float
z = 1j # complex
#convert from int to float:
a = float(x)
#convert from float to int:
b = int(y)
#convert from int to complex:
c = complex(x)
Python没有生成随机数的random（）函数，但Python有一个内置的模块，名为random，可用于生成随机数
import random
print(random.randrange(1, 10))
字符串
可以使用三个引号将多行字符串指定变量
a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""
print(a)
要获得字符串的长度，请使用len（）函数。
a = "Hello, World!"
print(len(a))
要检查字符串中是否存在某个短语或字符，可以在中使用关键字in或者not in
txt = "The best things in life are free!"
print("free" in txt)
txt = "The best things in life are free!"
print("expensive" not in txt)
upper（）方法以大写形式返回字符串
a = "Hello, World!"
print(a.upper())
lower（）方法以小写形式返回字符串
a = "Hello, World!"
print(a.lower())
strip（）方法从开头或结尾删除任何空格
a = " Hello, World! "
print(a.strip()) # returns "Hello, World!"
replace（）方法将一个字符串替换为另一个字符串
a = "Hello, World!"
print(a.replace("H", "J"))
split（）方法返回一个列表，其中指定分隔符之间的文本成为列表项。
a = "Hello, World!"
print(a.split(",")) # returns ['Hello', ' World!']
要连接或组合两个字符串，可以使用+运算符。
a = "Hello"
b = "World"
c = a + b
print(c)
format（）方法接受传递的参数，对其进行格式化，并将其放置在占位符｛｝所在的字符串中
age = 36
txt = "My name is John, and I am {}"
print(txt.format(age))
format（）方法接受无限数量的参数，并放置在相应的占位符中：
quantity = 3
itemno = 567
price = 49.95
myorder = "I want {} pieces of item {} for {} dollars."
print(myorder.format(quantity, itemno, price))
您可以使用索引号｛0｝，以确保参数放置在正确的占位符中
quantity = 3
itemno = 567
price = 49.95
myorder = "I want to pay {2} dollars for {0} pieces of item {1}."
print(myorder.format(quantity, itemno, price))
要在字符串中插入非法字符，请使用转义字符。
txt = "We are the so-called \"Vikings\" from the north."
布尔值
除了空值（如（）、[]、｛｝、“、数字0和值None）之外，没有多少值的计算结果为False。当然，值False的计算结果为False。
# 下面将返回False
bool(False)
bool(None)
bool(0)
bool("")
bool(())
bool([])
bool({})
Python运算符
Python算术运算符
| Operator | Name | Example |
|---|---|---|
| + | Addition | x + y |
| - | Subtraction | x - y |
| * | Multiplication | x * y |
| / | Division | x / y |
| % | Modulus | x % y |
| ** | Exponentiation | x ** y |
| // | Floor division | x // y |
赋值运算符
| Operator | Example | Same As |
|---|---|---|
| = | x = 5 | x = 5 |
| += | x += 3 | x = x + 3 |
| -= | x -= 3 | x = x - 3 |
| *= | x *= 3 | x = x * 3 |
| /= | x /= 3 | x = x / 3 |
| %= | x %= 3 | x = x % 3 |
| //= | x //= 3 | x = x // 3 |
| **= | x **= 3 | x = x ** 3 |
| &= | x &= 3 | x = x & 3 |
| |= | x |= 3 | x = x | 3 |
| ^= | x ^= 3 | x = x ^ 3 |
| >>= | x >>= 3 | x = x >> 3 |
| <<= | x <<= 3 | x = x << 3 |
比较运算符
| Operator | Name | Example |
|---|---|---|
| == | Equal | x == y |
| != | Not equal | x != y |
| > | Greater than | x > y |
| < | Less than | x < y |
| >= | Greater than or equal to | x >= y |
| <= | Less than or equal to | x <= y |
逻辑运算符
| Operator | Description | Example |
|---|---|---|
| and | Returns True if both statements are true | x < 5 and x < 10 |
| or | Returns True if one of the statements is true | x < 5 or x < 4 |
| not | Reverse the result, returns False if the result is true | not(x < 5 and x < 10) |
身份运算符
| Operator | Description | Example |
|---|---|---|
| is | Returns True if both variables are the same object | x is y |
| is not | Returns True if both variables are not the same object | x is not y |
成员运算符
| Operator | Description | Example |
|---|---|---|
| in | Returns True if a sequence with the specified value is present in the object | x in y |
| not in | Returns True if a sequence with the specified value is not present in the object | x not in y |
位运算符
| Operator | Name | Description |
|---|---|---|
| & | AND | Sets each bit to 1 if both bits are 1 |
| | | OR | Sets each bit to 1 if one of two bits is 1 |
| ^ | XOR | Sets each bit to 1 if only one of two bits is 1 |
| ~ | NOT | Inverts all the bits |
| << | Zero fill left shift | Shift left by pushing zeros in from the right and let the leftmost bits fall off |
| >> | Signed right shift | Shift right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off |