2019-05-24
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一、
# splitlines() 以换行切割字符串
s = ”’日照香炉生紫烟\n疑是银河落九天\n飞流直下三千尺”’
print(s.splitlines())
二、
# join() 将列表按照指定字符串连接
list1 = [‘日照香炉生紫烟’,’疑是银河落九天’,’飞流直下三千尺’]
s = ‘*’.join(list1)
print(s)
三、
# ljust() 指定字符串的长度，内容靠左边
s = ‘abc’
print(len(s))
print(s.ljust(5, ‘#’))
四、
# ljust() 指定字符串的长度，内容靠左边,不足的地方用空格填充，默认空格，返回字符串
s = ‘abc’
print(len(s))
print(s.ljust(5)+’aa’)# center() 指定字符串长度，内容居中,不足的地方用空格填充，默认空格，返回字符串
print(s.center(5, ‘#’))# rjust() 指定字符串的长度，内容靠右边,不足的地方用空格填充，默认空格，返回字符串
print(s.rjust(5, ‘#’))五、
# strip() 去掉左右两边指定字符，默认是去掉空格
# lstrip() 去掉左侧指定字符，默认空格
# rstrip() 去掉右侧指定字符，默认空格s = ‘ abc ‘
print(‘- – -‘+s.strip()+’- – -‘)
print(‘- – -‘+s+’- – -‘)s = ‘aaabcc’
print(s.lstrip(‘a’))
print(s.lstrip(‘b’))print(s.rstrip(‘b’))
print(s.rstrip(‘c’))———————————六、# zfill() 指定字符串长度
s = ‘abc’
print(s.zfill(5))———————————七、# maketrans() 生成用于字符串的映射表
# translate() 进行字符串替换
s = ‘今天晚上我吃的是小炒肉，可好吃了’
table = s.maketrans(‘小炒肉’, ‘大白菜’)
print(table)
print(s.translate(table))——————————–八、help(list)———————-Help on class list in module builtins:
class list(object)
| list(iterable=(), /)
|
| Built-in mutable sequence.
|
| If no argument is given, the constructor creates a new empty list.
| The argument must be an iterable if specified.
|
| Methods defined here:
|
| __add__(self, value, /)
| Return self+value.
|
| __contains__(self, key, /)
| Return key in self.
|
| __delitem__(self, key, /)
| Delete self[key].
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __getitem__(…)
| x.__getitem__(y) <==> x[y]
|
| __gt__(self, value, /)
| Return self>value.
|
| __iadd__(self, value, /)
| Implement self+=value.
|
| __imul__(self, value, /)
| Implement self*=value.
|
| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
|
| __iter__(self, /)
| Implement iter(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __len__(self, /)
| Return len(self).
|
| __lt__(self, value, /)
| Return self<value.
|
| __mul__(self, value, /)
| Return self*value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __repr__(self, /)
| Return repr(self).
|
| __reversed__(self, /)
| Return a reverse iterator over the list.
|
| __rmul__(self, value, /)
| Return value*self.
|
| __setitem__(self, key, value, /)
| Set self[key] to value.
|
| __sizeof__(self, /)
| Return the size of the list in memory, in bytes.
|
| append(self, object, /)
| Append object to the end of the list.
|
| clear(self, /)
| Remove all items from list.
|
| copy(self, /)
| Return a shallow copy of the list.
|
| count(self, value, /)
| Return number of occurrences of value.
|
| extend(self, iterable, /)
| Extend list by appending elements from the iterable.
|
| index(self, value, start=0, stop=9223372036854775807, /)
| Return first index of value.
|
| Raises ValueError if the value is not present.
|
| insert(self, index, object, /)
| Insert object before index.
|
| pop(self, index=-1, /)
| Remove and return item at index (default last).
|
| Raises IndexError if list is empty or index is out of range.
|
| remove(self, value, /)
| Remove first occurrence of value.
|
| Raises ValueError if the value is not present.
|
| reverse(self, /)
| Reverse *IN PLACE*.
|
| sort(self, /, *, key=None, reverse=False)
| Stable sort *IN PLACE*.
|
| ———————————————————————-
| Static methods defined here:
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| ———————————————————————-
| Data and other attributes defined here:
|
| __hash__ = None—————————–九、# append 向列表末尾添加新元素 返回值None
list1 = [1,2,3,4,5]
print(list1.append(5))—————————-十、# count() 计算某个元素在列表中出现的次数
list1 = [1,1,2,5,1,3]
print(list1.count(5))—————————-十一、# extend() 将一个列表继承另一个列表
list1 = [1,2,3,4,5]
list2 = [6,7,8,9,10]
list3 = list1.extend(list2)
print(list1)
print(list2)
print(list3)
print(list1 + list2)——————————十二、# index() 获取值在列表中的索引
list1 = [1,2,3,4,5,3]
print(list1.index(3))
#print(list1.index)
print(list1.index(3, 2, 5))—————————–十三、# insert() 在指定位置前插入元素 2个参数
list1 = [1,2,3,4,5]
list1.insert(2,9)
print(list1)——————————-十四、# pop() 根据索引移除列表内一个元素，不给索引默认移除最后一个
list1 = [1,2,3,4,5]
list1.pop()
print(list1)——————————-十五、# remove() 移除列表中指定的值 返回None
list1 = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’]
list1.remove(‘b’)
print(list1)——————————–十六、# sort() 排序 默认从小到大
list1 = [5,2,4,6,1,9]
list1.sort()
print(list1)——————-十七、# reverse() 列表反转
list1 = [1,2,3,4]
list1.reverse()
print(list1)———————-十八、# sort() 排序 默认从小到大
list1 = [5,2,4,6,1,9]
list1.sort()
print(list1)#从大到小
list1.sort(reverse=True)————————十九、# count() 计算某个元素在元组中出现的次数
tuple1 = (3, 2, 4, 1, 3, 6)
print(tuple1.count(3))————————二十、# index() 获取值在元组中的索引
tuple1 = (3, 2, 4, 1, 3, 6)
print(tuple1.index(3))————————-二十一、# index() 获取值在元组中的索引
tuple1 = (3, 2, 4, 1, 3, 6)
print(tuple1.index(3))
print(tuple1.index(3,1,5))————————二十二、# copy() 复制字典
dict1 = {‘a’:1, ‘b’:2, ‘c’:3}
dict2 = dict1.copy()
print(dict2)————————-二十三、# fromkeys() 按照指定的序列为键创建字典，值都是一样的
list1 = [‘a’, ‘b’, ‘c’]
dict1 = {}.fromkeys(list1)
dict2 = {}.fromkeys(list1, 3)
print(dict1,dict2)————————–二十四、# get() 根据键获取指定的值
dict1 = {‘a’:1, ‘b’:2, ‘c’:3}
print(dict1.get(‘b’))————————–二十五、# get() 根据键获取指定的值 找不到的键如何没默认值则返回默认值，如果没设默认值，则返回None
dict1 = {‘a’:1, ‘b’:2, ‘c’:3}
print(dict1.get(‘b’))
print(dict1.get(‘d’))
print(dict1.get(‘d’, 4))——————————–二十六、# items() 将字典变成类似于元组的形式方便遍历
dict1 = {‘a’:1, ‘b’:2, ‘c’:3}
for k,v in dict1.items():
print(k,v)print(dict1.items())——————————-二十七、# popitem() 移除字典的键值对 返回移除的键和值
dict1 = {‘d’:4, ‘a’:1, ‘b’:2, ‘c’:3}
print(dict1.popitem())———————————二十八、# setdefault() 在字典里添加一个元素
dict1 = {‘d’:4, ‘a’:1, ‘b’:2, ‘c’:3}
print(dict1.setdefault(‘e’,5))
print(dict1)——————————-二十九、# update() 修改字典中的值
dict1 = {‘d’:4, ‘a’:1, ‘b’:2, ‘c’:3}
dict1.update({‘a’:3})
print(dict1)———————————-三十、help(set)———————Help on class set in module builtins:
class set(object)
| set() -> new empty set object
| set(iterable) -> new set object
|
| Build an unordered collection of unique elements.
|
| Methods defined here:
|
| __and__(self, value, /)
| Return self&value.
|
| __contains__(…)
| x.__contains__(y) <==> y in x.
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __iand__(self, value, /)
| Return self&=value.
|
| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
|
| __ior__(self, value, /)
| Return self|=value.
|
| __isub__(self, value, /)
| Return self-=value.
|
| __iter__(self, /)
| Implement iter(self).
|
| __ixor__(self, value, /)
| Return self^=value.
|
| __le__(self, value, /)
| Return self<=value.
|
| __len__(self, /)
| Return len(self).
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __or__(self, value, /)
| Return self|value.
|
| __rand__(self, value, /)
| Return value&self.
|
| __reduce__(…)
| Return state information for pickling.
|
| __repr__(self, /)
| Return repr(self).
|
| __ror__(self, value, /)
| Return value|self.
|
| __rsub__(self, value, /)
| Return value-self.
|
| __rxor__(self, value, /)
| Return value^self.
|
| __sizeof__(…)
| S.__sizeof__() -> size of S in memory, in bytes
|
| __sub__(self, value, /)
| Return self-value.
|
| __xor__(self, value, /)
| Return self^value.
|
| add(…)
| Add an element to a set.
|
| This has no effect if the element is already present.
|
| clear(…)
| Remove all elements from this set.
|
| copy(…)
| Return a shallow copy of a set.
|
| difference(…)
| Return the difference of two or more sets as a new set.
|
| (i.e. all elements that are in this set but not the others.)
|
| difference_update(…)
| Remove all elements of another set from this set.
|
| discard(…)
| Remove an element from a set if it is a member.
|
| If the element is not a member, do nothing.
|
| intersection(…)
| Return the intersection of two sets as a new set.
|
| (i.e. all elements that are in both sets.)
|
| intersection_update(…)
| Update a set with the intersection of itself and another.
|
| isdisjoint(…)
| Return True if two sets have a null intersection.
|
| issubset(…)
| Report whether another set contains this set.
|
| issuperset(…)
| Report whether this set contains another set.
|
| pop(…)
| Remove and return an arbitrary set element.
| Raises KeyError if the set is empty.
|
| remove(…)
| Remove an element from a set; it must be a member.
|
| If the element is not a member, raise a KeyError.
|
| symmetric_difference(…)
| Return the symmetric difference of two sets as a new set.
|
| (i.e. all elements that are in exactly one of the sets.)
|
| symmetric_difference_update(…)
| Update a set with the symmetric difference of itself and another.
|
| union(…)
| Return the union of sets as a new set.
|
| (i.e. all elements that are in either set.)
|
| update(…)
| Update a set with the union of itself and others.
|
| ———————————————————————-
| Static methods defined here:
| ————————–三十一、a = set()
print(a)
list1 = [1,2,3,4]
a = set(list1)
print(a)———————–三十二、# add() 向集合中添加元素
set1 = {5, 1, 2, 3, 4}
set1.add(6)
print(set1)————————–三十三、# pop() 随机弹出一个元素
a = {‘a’, ‘b’, ‘f’, 4}
a.pop()
print(a)————————-三十四、# remove() 删除集合中的某个值
a = {‘a’, ‘b’, ‘f’, 4}
a.remove(4)
print(a)—————————-三十五、# discard() 删除集合中的某个值，如果这个值不在集合中什么也不做
a = {‘a’, ‘b’, ‘f’, 4}
a.discard(4)
print(a)—————————-三十六、# discard() 删除集合中的某个值，如果这个值不在集合中什么也不做
a = {‘a’, ‘b’, ‘f’, 4}
a.discard(4)
print(a)
a.discard(4)
print(a)—————————-三十七、# difference() 差集 概念：
# difference_update() 区别就是第一个返回一个新的集合，第二个是把原来集合覆盖
set1 = {1,2,3,4,7}
set2 = {2,4,8,111,24}
set3 = set1.difference(set2)
print(set3)
set4 = set1.difference_update(set2)
print(set4)—————————三十八、
