万恶之源-Python基础知识补充

s = "alex"
print(s.encode("utf-8")) # 将字符串编码成UTF-8
print(s.encode("GBK")) # 将字符串编码成GBK
结果:
b'alex'
b'alex'
s = "中"
print(s.encode("UTF-8")) # 中⽂编码成UTF-8
print(s.encode("GBK")) # 中⽂编码成GBK
结果:
b'\xe4\xb8\xad'
b'\xd6\xd0'

s = "我叫李嘉诚"
print(s.encode("utf-8")) #
b'\xe6\x88\x91\xe5\x8f\xab\xe6\x9d\x8e\xe5\x98\x89\xe8\xaf\x9a'
print(b'\xe6\x88\x91\xe5\x8f\xab\xe6\x9d\x8e\xe5\x98\x89\xe8\xaf\x9a'.decod
e("utf-8")) # 解码

s = "我是⽂字" bs = s.encode("GBK") 
# 我们这样可以获取到GBK的⽂字 
# 把GBK转换成UTF-8 
# ⾸先要把GBK转换成unicode. 也就是需要解码 
s = bs.decode("GBK") # 解码 
# 然后需要进⾏重新编码成UTF-8 
bss = s.encode("UTF-8") # 重新编码 
print(bss)

lst = [1,2,3,4,5,6]

for i in lst:
    lst.append(7) # 这样写法就会一直持续添加7
    print(lst)
print(lst)   

li = [11, 22, 33, 44]
for e in li:
 li.remove(e)
print(li)
结果:
[22, 44]

li = [11, 22, 33, 44]
for i in range(0, len(li)):
 del li[i]
print(li)
结果: 报错
# i= 0, 1, 2 删除的时候li[0] 被删除之后. 后⾯⼀个就变成了第0个.
# 以此类推. 当i = 2的时候. list中只有⼀个元素. 但是这个时候删除的是第2个 肯定报错啊

for el in li:
 li.pop() # pop也不⾏
print(li)
结果:
[11, 22]

for i in range(0, len(li)): # 循环len(li)次, 然后从后往前删除
 li.pop()
print(li)

li = [11, 22, 33, 44]
del_li = []
for e in li:
 del_li.append(e)
for e in del_li:
 li.remove(e)

print(li)

dic = dict.fromkeys(["jay", "JJ"], ["周杰伦", "麻花藤"])
print(dic)
结果:
{'jay': ['周杰伦', '麻花藤'], 'JJ': ['周杰伦', '麻花藤']}

dic = {'k1': 'alex', 'k2': 'wusir', 's1': '⾦⽼板'}
# 删除key中带有'k'的元素
for k in dic:
  if 'k' in k:
 del dic[k] # dictionary changed size during iteration, 在循环迭
代的时候不允许进⾏删除操作
print(dic)

dic = {'k1': 'alex', 'k2': 'wusir', 's1': '⾦⽼板'}
dic_del_list = []
# 删除key中带有'k'的元素
for k in dic:
 if 'k' in k:
 dic_del_list.append(k)
for el in dic_del_list:
 del dic[el]
print(dic)

lst1 = ["⾦⽑狮王", "紫衫⻰王", "⽩眉鹰王", "⻘翼蝠王"]
lst2 = lst1
print(lst1)
print(lst2)
lst1.append("杨逍")
print(lst1)
print(lst2)
结果:
['⾦⽑狮王', '紫衫⻰王', '⽩眉鹰王', '⻘翼蝠王', '杨逍']
['⾦⽑狮王', '紫衫⻰王', '⽩眉鹰王', '⻘翼蝠王', '杨逍']


dic1 = {"id": 123, "name": "谢逊"}
dic2 = dic1
print(dic1)
print(dic2)
dic1['name'] = "范瑶"
print(dic1)
print(dic2)
结果:
{'id': 123, 'name': '谢逊'}
{'id': 123, 'name': '谢逊'}
{'id': 123, 'name': '范瑶'}
{'id': 123, 'name': '范瑶'}

lst1 = ["何炅", "杜海涛","周渝⺠"]
lst2 = lst1.copy()
lst1.append("李嘉诚")
print(lst1)
print(lst2)
print(id(lst1), id(lst2))
结果:
两个lst完全不⼀样. 内存地址和内容也不⼀样. 发现实现了内存的拷⻉
lst1 = ["何炅", "杜海涛","周渝⺠", ["麻花藤", "⻢芸", "周笔畅"]]
lst2 = lst1.copy()
lst1[3].append("⽆敌是多磨寂寞")
print(lst1)
print(lst2)
print(id(lst1[3]), id(lst2[3]))
结果:
['何炅', '杜海涛', '周渝⺠', ['麻花藤', '⻢芸', '周笔畅', '⽆敌是多磨寂寞']]
['何炅', '杜海涛', '周渝⺠', ['麻花藤', '⻢芸', '周笔畅', '⽆敌是多磨寂寞']]
4417248328 4417248328

import copy
lst1 = ["何炅", "杜海涛","周渝⺠", ["麻花藤", "⻢芸", "周笔畅"]]
lst2 = copy.deepcopy(lst1)
lst1[3].append("⽆敌是多磨寂寞")
print(lst1)
print(lst2)
print(id(lst1[3]), id(lst2[3]))
结果:
['何炅', '杜海涛', '周渝⺠', ['麻花藤', '⻢芸', '周笔畅', '⽆敌是多磨寂寞']]
['何炅', '杜海涛', '周渝⺠', ['麻花藤', '⻢芸', '周笔畅']]
4447221448 4447233800

a = [1, 2]
a[1] = a
print(a[1])　　

f = open("护⼠少妇嫩模萝莉.txt",mode="r", encoding="utf-8")
cOntent= f.read()
print(content)
f.close()

f = open("护⼠少妇嫩模萝莉.txt",mode="rb" )
cOntent= f.read()
print(content)
f.close()
结果:
b'\xe6\xaf\x85\xe5\x93\xa5, \xe5\xa4\xaa\xe7\x99\xbd,
wuse\n\xe5\x91\xb5\xe5\x91\xb5\n\xe6\x97\xa5\xe5\xa4\xa9'