1. 列表的插入
a= [1, 2, 3]
b= [4, 5, 6]
a[1:1] = [7, 8 ,9]
print(a)
# a = [1, 7, 8, 9, 2, 3]
2. 列表的扩充
a= [1, 2, 3]
a.extend(b)
print(a)
# result : a -> [1, 2, 3, 4, 5, 6]
# difference between a + b and a.extend[b] is that a + b doesn't change the value of a
x = {}
y = x
x['key'] = 'value'
# y = {'key' : 'value'}
x = {}
# y = {'key' : 'value'}
3. strip的使用
str = "* ** this **is the use*of * * strip **"
str = str.strip('*')
print(str)
#result : ' ** this **is the use*of * * strip '
# 只能对 strip 字符串两边的字符其作用
4. 对于字典的 print 的使用
phone = {
'mc': '123'
}
print("the num is %(mc)s" % phone)
# result : the num is 123
5. 字典的清除 ( clear )
clear 会清除字典的所有项
x = {}
y = x
x['key'] = 'value'
# y = {'key': 'value'}
x = {}
# y = {'key': 'value'} # 未将字典清除
x = {}
y = x
x['key'] = 'value'
# y = {'key': 'value'}
x.clear()
# y = {} # 将字典清除
6. 对字典深复制与浅复制的区别
7. 字典中函数的使用
- 若直接采用索引来检索,当不存在时会报错,而直接用 get 时,会返回None
- popitem 会弹出字典中随机的一项
8. 异常处理
异常处理中直接使用 except: 捕获所有异常是危险的,因为它会隐藏未想到的错误
def flat(nested): try: try:nested+'' except TypeError: print(1) pass else: print(2) raise TypeError for s in nested: for k in s: print(k) except TypeError: print(3) >>> flat('222') 3 2 >>>