标签：-- split() 出现 更改 方法总结 方式 传参 spl ali
| 加 | + |
|---|---|
| 减 | - |
| 乘 | * |
| 除 | / |
| 取余 | % |
| 余数取整 | // |
| 掌握 | 熟悉 | 了解 |
|---|---|---|
| 按索引取值 ,strs[0] | lstrip,rstrip | find,rfind |
| 切片,str[::-1] | lower,upper | index,rindex |
| 长度,len[strs] | startswith,endswith | count |
| 成员运算,print{" ‘llo‘ in strs"} | rsplit | center,ljust,rjust,zfill |
| 移除空白, strs.strip() | join | expandtabs |
| 切割,strs.split() | replace | captalize,swapcase,title |
| 循环,for i in strs: | isdigit | is |
==a = "Hello World"==
按索引取值:
print{a[0]}
# H
'''
总结:
1. 索引取值可以根据索引随时拿到字符串中任意一个字符.在工作中经常使用
'''切片
print{a[::-1]}
print(a[-1:-6:-1])
# dlroW olleH
# dlroW
'''
总结:
1. 切片不仅可以截取字符串中的任意一部分,同时也可以将字符串进行反转操作.
'''长度,len()
print(len(a))
# 11
'''
总结:
1. 经常会根据字符串的长度 获取对应索引.在工作中经常使用.
'''成员运算,in/ not in
print("ello" in a)
# True移除空白,strip,lstrip,rstrip
b = " dajiahao!wo jiao panlifu "
print(b.strip())
# dajiahao!wo jiao panlifu 默认直接删除字符串两端的空白
print(b.strip(" adwuflinp"))
# jiahao!wo jiao 直接从两端进行删除,只要传参的字符串中包含b字符串两端的字符,即可删除,没有则停止
# lstrip 左移除
print(b.lstrip())
print(b.lstrip(" jadu"))
# dajiahao!wo jiao panlifu
# iahao!wo jiao panlifu
# rstrip 右移除
print(b.rstrip())
print(b.rstrip(" aflui"))
# dajiahao!wo jiao panlifu
# dajiahao!wo jiao pan切割, split,rsplit
print(a.split(" ",1))
# ['Hello', 'World']
print(a.split("o",2))
print(a.split("o"))
# ['Hell', ' W', 'rld']
# ['Hell', ' W', 'rld']
# rsplit 右切割
print(a.rsplit())
# ['Hel', 'o Wor', 'd']for循环
for i in a:
print(i)
'''
H
e
l
l
o
W
o
r
l
d
''' 大小写, lower/upper
print(a.lower())
# hello world
print(a.upper())
# HELLO WORLD
'''
总结:
1. 通常在输入验证码的时候,不区分大小写.可能就是将对应的字符串统一变成了大写或小写
'''判断区间内的首字母是否相同, startswith,endswith
print(a.startswith('r',0,len(a)))
# False
print(a.startswith('H',0,len(a)))
# True
print(a.endswith('e',0,len(a)))
# False
print(a.endswith('d',0,len(a)))
# True
'''
总结:
1. startswith,它可以判断区间内(顾头不顾尾)首字母是否为指定字符,返回bool值
2. endswith,它可以判断区间内(顾头不顾尾)尾字母是否为指定字符,返回bool值
'''连接,join
test_list = ["etc","plf","lt","xs","cd"]
print("/".join(test_list))
# etc/plf/lt/xs/cd
print('/'.join(a))
# h/e/l/l/o/ /w/o/r/l/d
'''
总结:
1. 用来连接各个元素,一般用于路径的拼接
'''替换replace
print(a.replace("o","P"))
# HellP WPrld
'''
总结:
1. 将字符串中的字符替换成指定字符
'''判断是否为数字isdigit
print(a.isdigit())
# False
test_str = "123"
print(test_str.isdigit())
# True
'''
总结:
1. 判断字符串中是否全是数字
2. 注意:
当数字字符串中含有空格时,isdigit依然会返回True,因此我们使用数字时,一定要记得将空格替换掉!
'''查找 find,rfind
print(a.find("H"))
# 0
print(a.find("d"))
# 10
print(a.find("p"))
# -1
print(a.find("ell"))
# 1
'''
总结:
1. 当传入对应字符时,返回对应字符的下标.如果没有对应字符,则返回-1
2. 当传入字符串时,返回对应字符串第一个字符的下标.如果没有,则返回-1
'''index,rindex
print(a.index("H"))
# 0
print(a.index("d"))
# 10
print(a.index("p"))
# 抛异常,程序中断
print(a.index("ell"))
# 1
'''
总结:
1. 当传入对应字符时,返回对应字符的下标.如果没有对应字符,则抛异常
2. 当传入字符串时,返回对应字符串第一个字符的下标.如果没有,则抛异常
3. 与find相比,find的方式更加友好
'''count,字符串出现的次数
print(a.count("o"))
# 2center,ljust,rjust,zfill
# center 居中
print(a.center(30,"*"))
# *********Hello World**********
# ljust 居左
print(a.ljust(30,"*"))
# Hello World*******************
# rjust 居右
print(a.rjust(30,"*"))
# *******************Hello World
# zfill 默认以0填充
print(a.zfill(30))
# 0000000000000000000Hello Worldexpandtabs, 设置制表符距离,默认为8
print("aaa\tbbb".expandtabs())
# aaa bbb
print("aaa\tbbb".expandtabs(4))
# aaa bbbcapitalize,swapcase,title
print(a.capitalize())
# Hello world
print(a.swapcase())
# hELLO wORLD
a = "hello world"
print(a.title())
# Hello World| 增 | 删 | 改 | 查 |
|---|---|---|---|
| append(元素) | del 列表 | my_list[下标]="修改内容" | in/not in |
| extend(列表) | pop() | count(元素) | |
| insert(位置,"元素") | remove("元素") | index("元素") | |
追加 , append
a = ["plf","lt","xs","cd"]
a.append('www')
print(a)
# ['plf', 'lt', 'xs', 'cd', 'www']增加列表
a = ["plf","lt","xs","cd"]
b = ["ls","ww","zhy"]
a.extend(b)
print(a)
# ['plf', 'lt', 'xs', 'cd', 'ls', 'ww', 'zhy']插入数据
a = ["plf","lt","xs","cd"]
a.insert(1,"www")
print(a)
# ['plf', 'www', 'lt', 'xs', 'cd']删除列表
a = ["plf","lt","xs","cd"]
a.insert(1,"www")
del a
print(a)
'''
NameError Traceback (most recent call last)
<ipython-input-16-71b7731a4ef0> in <module>
2 a.insert(1,"www")
3 del a
----> 4 print(a)
NameError: name 'a' is not defined
'''pop()
a = ["plf","lt","xs","cd"]
b = a.pop()
print("a的值%s\n%s"%(a,b))
'''
a的值:['plf', 'lt', 'xs']
b的值:cd
'''remove("元素")
a = ["lt","plf","lt","xs","cd","cd"]
a.remove("cd")
a.remove("lt")
print("a的值:%s"%(a))
'''
a的值:['plf', 'lt', 'xs', 'cd']
'''根据下标更改
a = ["lt","plf","lt","xs","cd","cd"]
a[0] = "gunkai"
print("a的值:%s"%(a))
'''
a的值:['gunkai', 'plf', 'lt', 'xs', 'cd', 'cd']
'''in/not in 是否在
a = ["lt","plf","lt","xs","cd","cd"]
print(bool("xxxx" in a))
print(bool("xxxx" not in a))
'''
False
True
'''count(元素)
a = ["lt","plf","lt","xs","cd","cd"]
print(a.count("lt"))
'''
2
'''index("元素")
a = ["lt","plf","lt","xs","cd","cd"]
print(a.index("lt"))
'''
0
'''len()
a = ["lt","plf","lt","xs","cd","cd"]
print(len(a))
'''
6
'''max(list) 返回列表元素最大值
a = ["lt","plf","lt","xs","cd","cd"]
b = ["plf","zj","xn","lt"]
c = [1,200,3,4,5,6,7,8,9,100,111]
print(max(a))
print(max(b))
print(max(c))
'''
xs
zj
200
'''
# min(list) 同理,返回列表元素最小值list(seq)
a = "hello,world"
b = (1,2,3,4,5,6)
print(list(a))
print(list(b))
'''
['h', 'e', 'l', 'l', 'o', ',', 'w', 'o', 'r', 'l', 'd']
[1, 2, 3, 4, 5, 6]
'''clear, 清除
name_list = ['nick', 'jason', 'tank', 'sean']
name_list.clear()
print(f"name_list: {name_list}")
'''
name_list: []
'''copy, 拷贝
name_list = ['nick', 'jason', 'tank', 'sean']
print(f"name_list.copy(): {name_list.copy()}")
'''
name_list.copy(): ['nick', 'jason', 'tank', 'sean']
'''reverse, 反转
name_list = ['nick', 'jason', 'tank', 'sean']
name_list.reverse()
print(f"name_list: {name_list}")
'''
name_list: ['sean', 'tank', 'jason', 'nick']
'''sort
a = [2113,3123,4,31,115,17,82,123,55,21]
a.sort()
print(a)
a.sort(reverse=True)
print(a)
'''
[4, 17, 21, 31, 55, 82, 115, 123, 2113, 3123]
[3123, 2113, 123, 115, 82, 55, 31, 21, 17, 4]
'''| 增 | 删 | 改 | 查 |
|---|---|---|---|
| info[‘键‘] = 数据 | del | info["键"] = 要修改的元素 | print(info["键"]) |
| update() | pop() | print(info.get("不存在的键")) | |
| fromkeys() | popitem() | for key,value in info.itmes() | |
| setdefault() | keys(),values(),items() | ||
info[‘键‘] = 数据
a = {"name":"plf","age":"20","sex":"nan"}
a["address"] = "Chinese"
print(a)
'''
{'name': 'plf', 'age': '20', 'sex': 'nan', 'address': 'Chinese'}
'''update()
a = {"name":"plf","age":"20","sex":"nan"}
b = {"address":"Chinese"}
a.update(b)
print(a)
'''
{'name': 'plf', 'age': '20', 'sex': 'nan', 'address': 'Chinese'}
'''fromkeys()
c_dic = dict.fromkeys(['name','age','sex'],None)
print(c_dic)
'''
{'name': None, 'age': None, 'sex': None}
'''setdefault()
# dic之setdefault()，有指定key不会改变值；无指定key则改变值
dic = {'a': 1, 'b': 2}
print(f"dic.setdefault('a'): {dic.setdefault('a',3)}")
print(f"dic: {dic}")
print(f"dic.setdefault('c'): {dic.setdefault('c',3)}")
print(f"dic: {dic}")
'''
dic.setdefault('a'): 1
dic: {'a': 1, 'b': 2}
dic.setdefault('c'): 3
dic: {'a': 1, 'b': 2, 'c': 3}
'''del
dic = {'a': 1, 'b': 2}
del dic['a']
print(dic)
del dic
print(dic)
'''
{'b': 2}
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
<ipython-input-69-aded9265c051> in <module>
4 print(dic)
5 del dic
----> 6 print(dic)
NameError: name 'dic' is not defined
'''pop()
# dic之删除pop()
dic = {'a': 1, 'b': 2}
dic.pop('a') # 指定元素删除
print(f"dic.pop('b'): {dic.pop('b')}")
print(f"dic.get('a'): {dic.get('a')}")
'''
dic.pop('b'): 2
dic.get('a'): None
'''popitems()
dic = {'a': 1, 'b': 2}
print(f"dic.popitem(): {dic.popitem()}") # 随机删除一个元素，无法指定
'''
dic.popitem(): ('b', 2)
'''标签：-- split() 出现 更改 方法总结 方式 传参 spl ali
原文地址：https://www.cnblogs.com/plf-Jack/p/10914294.html
