a = [1,2,3]
display(a)
结果如下:
b = list("abcd")
display(b)
结果如下:
c = list(range(10))
display(c)
结果如下:
d = [i for i in range(10)]
display(d)
结果如下:
e = list()
display(e)
f = []
display(f)
结果如下:
a = [3,1.43,True,"哈哈"]
b = []
display(id(b))
for i in a:
b.append(i)
display(b)
display(id(b))
结果如下:
综上所示:我们发现在列表尾部添加元素后,b的存储地址前后并没有改变属于原地操作列表,这样的话对内存的开销较小。
a = ["我很好",4,5,6]
b = [1,2,3,"嘿嘿"]
display(b)
display(id(b))
b.extend(a)
display(b)
display(id(b))
结果如下:
a = [20,10,40,30]
display(id(a))
b = sorted(a)
display(b)
display(id(b))
结果如下:
c = [50,10,100,30]
display(id(c))
c.sort()
display(c)
display(id(c))
结果如下:
a = {"name":"张三","age":18,"job":"teacher"}
display(a)
结果如下:
b = dict(name="黄伟",age=18,job="teacher")
display(b)
#传入一个元组组成的列表
c = dict([("name","黄伟"),("age",18),("job","teacher")])
display(c)
结果如下:
list1 = ["name","age","job"]
list2 = ["黄伟",18,"teacher"]
d = dict(zip(list1,list2))
display(d)
结果如下:
e = {}
display(e)
f = dict()
display(f)
结果如下:
#传入一个由字典的"键"组成的列表;
list1 = ["name","age","job"]
g = dict.fromkeys(list1)
display(g)
结果如下:
a = {"name":"张三","age":18,"job":"teacher"}
display(a)
display(a.get("name"))
display(a.get("weight"))
结果如下:
a = {"name":"张三","age":18,"job":"teacher"}
display(a)
display(a.items)
for i in a.items():
print(i)
结果如下:
a = {"name":"张三","age":18,"job":"teacher"}
display(a)
display(a.keys())
display(a.values())
结果如下:
import time
t1 = time.time()
s = ""
for i in range(1000000):
s += "哈哈"
t2 = time.time()
display("用时:" + str(t2-t1))
t3 = time.time()
l = []
for i in range(1000000):
l.append("哈哈")
m = "".join(l)
t4 = time.time()
display("用时:" + str(t4-t3))
结果如下:
综上所述:进行字符串拼接,推荐使用"join"进行字符串拼接,少用"+"。
操作如下:
p = 'ab#'
q = 'ab#'
display(id(p),id(q))
# 判断两个对象的值是不是相等;
display(p == q)
# 判断两个对象是不是同一个对象;
display(p is q)
结果如下:
m = '12_abv'
n = '12_abv'
display(id(m))
display(id(n))
display(m == n)
display(m is n)
p = 'ab#'
q = 'ab#'
display(id(p))
display(id(q))
display(p == q)
display(p is q)
结果如下: