Python3——字符串操作（仅去空格、深复制、浅复制、连接、查找、切片）

字符串常用操作

import copy
# 去掉空格
string = " python "
both = string.strip()
print(both)
left = string.lstrip()
print(left)
right1 = string.rstrip()
print(right1)


# 复制字符串

a = "python"
b = a
c = copy.copy(a) # 浅copy内存地址一致
d = copy.deepcopy(a)
print(b)
# c = c + "test"
print("b:", b, "地址", id(b))
print("c:", c, "地址", id(c))
print("a:", a, "地址", id(a))
print("d:", d, "地址", id(d))
'''
b: python 地址 39017808
c: python 地址 39017808
a: python 地址 39017808
d: python 地址 39017808
'''
list1 = ["abc", "def",["aa","bb"]]
bb = list1
cc = copy.copy(list1)
dd = copy.deepcopy(list1)
list1[2].append("cc")
list1.append("dd")
print("bb:", bb, "地址", id(bb), "=") # 直接赋值,默认浅拷贝传递对象的引用而已,原始列表改变，被赋值的b也会做相同的改变
# bb: ['abc', 'def', ['aa', 'bb', 'cc'], 'dd'] 地址 43509896 =
print("cc:", cc, "地址", id(cc), "copy")# 浅复制，子对象的值会随着被复制对象的改变而改变，
# cc: ['abc', 'def', ['aa', 'bb', 'cc']] 地址 43586760 copy
print("list1:", list1, "地址", id(list1))
# list1: ['abc', 'def', ['aa', 'bb', 'cc'], 'dd'] 地址 43509896
print("dd:", dd, "地址", id(dd), "deepcopy"),# 深复制，子对象的值不会随着被复制对象的改变而改变，
# dd: ['abc', 'def', ['aa', 'bb']] 地址 43586824 deepcopy

# 连接字符串
aa = "hello"
bb = "world"
dd = "bbbbb"
print(aa+bb)#连接两个字符串,helloworld
print(dd.join(aa))# hbbbbbebbbbblbbbbblbbbbbo
print(dd.join(aa+bb))#  hbbbbbebbbbblbbbbblbbbbbobbbbbwbbbbbobbbbbrbbbbblbbbbbd
list2 = ["1","3"]
print(dd.join(list2))# aabbbbbfff

# 查找字符串
aa = "hello"
bb = aa.find("e")
cc = "1234567"
dd = cc.find("4", 2, 6)
print("bb",bb) # 1
print("dd",dd) # 3


# 将字符串放入中心位置可指定长度以及位置两边字符
aa = "aabbd"
# bb = "bb"
cc = "c"
print(aa.center(7, cc))
num = aa.count("d")
print(num)


# 切片
str = "0123456789"
print(str[0:3]) #截取第一位到第三位的字符
print(str[:]) #截取字符串的全部字符
print(str[:-3]) #截取从头开始到倒数第三个字符之前
print(str[2]) #截取第三个字符
print(str[-1]) #截取倒数第一个字符
print(str[::-1]) #创造一个与原字符串顺序相反的字符串
print(str[-3:-1]) #截取倒数第三位与倒数第一位之前的字符
print(str[-3:]) #截取倒数第三位到结尾
print(str[:-5:-3]) #逆序截取，截取倒数第五位数与倒数第三位数之间