s1 = 'hello, world!'
s2 = "你好，世界！"
print(s1, s2)
# 以三個(gè)雙引號(hào)或單引號(hào)開頭的字符串可以折行
s3 = '''
hello, 
world!
'''
print(s3, end='')

#創(chuàng)建字符串
str="apple"
str1='orange'
print(type(str),type(str1))#<class 'str'> <class 'str'>

#\轉(zhuǎn)義字符作用:讓一些符號(hào)失去原有的意義
str2 = "\"李白\""
str3 = '\'原神\''
print(str2, str3)
# "李白" '原神'


#定義字符串的時(shí)候,單雙引號(hào)可以互相嵌套
str4="'原神,'啟動(dòng)！??！'"
print(str4)
# '原神,'啟動(dòng)！??！'

s1 = 'hello' + ' ' + 'world'
print(s1)    # hello world
s2 = '!' * 3
print(s2)    # !!!
s1 += s2     # s1 = s1 + s2
print(s1)    # hello world!!!
s1 *= 2      # s1 = s1 * 2
print(s1)    # hello world!!!hello world!!!

s1 = 'a whole new world'
s2 = 'hello world'
print(s1 == s2, s1 < s2)  # False True
print(s2 == 'hello world')  # True
print(s2 == 'Hello world')  # False
print(s2 != 'Hello world')  # True
s3 = '李白'
print(ord('李'), ord('白'))  # 26446 30333
s4 = '秦始皇'
print(ord('秦'), ord('始'), ord('皇'))  # 31206 22987 30343
print(s3 > s4, s3 <= s4)  # False True

s1 = str(123)
s2 = str(123)
s3 = s2
# 比較字符串的內(nèi)容
print(id(s1))#2293238767536
print(id(s2))#2293238767584
print(id(s3))#2293238767584
print(s1 == s2, s2 == s3)    # True True
# 比較字符串的內(nèi)存地址
print(s1 is s2, s2 is s3)    # False True

#以f開頭表示在字符串內(nèi)支持大括號(hào)內(nèi)的python表達(dá)式
import time
name = "py小王子"
t0 = time.time()
# 這里設(shè)一些耗時(shí)操作，用sleep模擬
time.sleep(10)
print(f'{name} done in {time.time() - t0:.2f}s')
# py小王子 done in 10.00s

s1 = 'hello, world'
print('wo' in s1)    # True
s2 = 'goodbye'
print(s2 in s1)      # False

s1 = 'hello'
for index in range(len(s1)):
    print(s1[index])

s1 = 'hello'
for ch in s1:
    print(ch)

str1="welcome"
print(str1[0]) #w
print(str1[3]) #c

str2 = "welcome to beijing"
'''
切片的語法:
字符串[start:end:step]截取的字符串包含開始下標(biāo)對(duì)應(yīng)的字符串
start表示開始下標(biāo)end表示結(jié)束下標(biāo)
step表示步長
'''
print(str2[0:3])  # wel 包含start不包含end
print(str2[1:])  # elcome to beijing  若只設(shè)置了start表示從開始下標(biāo)一直截取到最后
print(str2[:4])  # welc 若只設(shè)置了end表示從第一個(gè)字符開始一直截取到指定結(jié)束的位置
print(str2[1:4:2])  # ec
# print(str2[1:4:0])  # 在切片的時(shí)候,步長不能設(shè)置為0,ValueError: slice step cannot be zero
print(str2[::])  # welcome to beijing   若未設(shè)置開始和結(jié)束,表示復(fù)制字符串
print(str2[::-1])  # gnijieb ot emoclew   表示翻轉(zhuǎn)字符串
print(str2[-9:-3])  # o beij    start和end若都為負(fù)數(shù),表示從右邊開始數(shù)

str4 = "'原神,'啟動(dòng)?。?！'"
# 獲取字符串的長度len()
print(len(str4))  # 11

# count()在整個(gè)字符串中查找子字符串出現(xiàn)的次數(shù)
str = "電腦卡了,ss電腦呢?"
print(str.count("電腦"))  # 2
# 在指定區(qū)間內(nèi)查找出現(xiàn)的次數(shù)
print(str.count("電腦", 5, 30))  # 1

#find()查找子串在字符串中第一次出現(xiàn)的位置,返回的是下標(biāo),若未找到返回-1

ss3="123asdfASDCXaZ8765sahbzcd6a79"
print(ss3.find("a")) #3

print(ss3.find("y")) #-1 未找到子串,返回-1

#在指定區(qū)間內(nèi)查找
print(ss3.find("a",5,20)) #12

#rfind查找子串在字符串中最后一次出現(xiàn)的位置,返回的是下標(biāo),若未找到返回-1 print(ss3.rfind("a")) #25
print(ss3.rfind("y")) #-1

#index()功能和find類似在字符串中未找到的時(shí)候,直接報(bào)錯(cuò)
print(ss3.index("d")) #5 
#print(ss3.index("y"))#ValueError:substringnotfound

#max()min()依據(jù)ASCII碼進(jìn)行的獲取print(max(ss3)) #z
print(min(ss3)) #1

#2.字符串大小寫轉(zhuǎn)換upper()lower()
#upper()將字符串中的小寫字母轉(zhuǎn)換為大寫
str1="i Miss you Very Much!"
print(str1.upper()) #I MISS YOU VERY MUCH!

#lower()將字符串中的大寫字母轉(zhuǎn)化為小寫
print(str1.lower()) #i miss you very much!

#swapcase 將字符串中的大寫轉(zhuǎn)換為小寫,將小寫轉(zhuǎn)換為大寫]
print(str1.swapcase()) #I mISS YOU vERY mUCH!

#title()將英文中每個(gè)單詞的首字母轉(zhuǎn)換為大寫
str2="i love you forever!"
print(str2.title()) # I Love You Forever!

# strip()去除字符串兩邊的指定字符(默認(rèn)去除的是空格)
ss4 = " today is a nice day "
ss5 = "***today is a nice day****"
print(ss4)  # today is a nice day 
print(ss4.strip())  # today is a nice day
print(ss5)  # ***today is a nice day****
print(ss5.strip("*"))  # today is a nice day
# lstrip只去除左邊的指定字符(默認(rèn)去除的是空格)
print(ss5.lstrip("*"))  # today is a nice day****
# rstrip只去除右邊的指定字符(默認(rèn)去除的是空格)
print(ss5.rstrip("*"))  # ***today is a nice day

# split()以指定字符對(duì)字符串進(jìn)行分割(默認(rèn)是空格)
ss6 = "this is a string example.....wow!"
print(ss6.split())  # 以空格進(jìn)行分割['this','is','a','string','example.....wow!']
print(ss6.split("i"))  # ['th', 's ', 's a str', 'ng example.....wow!']

# splitlines()按照行切割
ss7 = '''將進(jìn)酒
君不見黃河之水天上來,奔流到海不復(fù)回.
君不見高堂明鏡悲白發(fā),************.
'''
print(ss7)
print(ss7.splitlines())  # ['將進(jìn)酒', '君不見黃河之水天上來,奔流到海不復(fù)回.', '君不見高堂明鏡悲白發(fā),************.']

# join以指定字符進(jìn)行合并字符串
ss8 = "-"
tuple1 = ("hello", "every", "body")
print(tuple1)  # ['將進(jìn)酒', '君不見黃河之水天上來,奔流到海不復(fù)回.', '君不見高堂明鏡悲白發(fā),************.']
print(ss8.join(tuple1))  # hello-every-body

# 替換
# replace()對(duì)字符串中的數(shù)據(jù)進(jìn)行替換
ss9 = "第五人格，啟動(dòng)?。〉谖迦烁?，真好玩?。?
print(ss9)
print(ss9.replace("第五人格", "***"))  # ***，啟動(dòng)??！***，真好玩??！
# 控制替換的字符的次數(shù)
print(ss9.replace("第五人格", "***", 1))  # ***，啟動(dòng)??！第五人格，真好玩??！

# 字符串判斷
# isupper()檢測字符串中的字母是否全部大寫
print("ASDqwe123".isupper())  # False
print("ASD123".isupper())  # True
print()

# islower()檢測字符串中的字母是否全部小寫
print("ASDqwe123".islower())  # False
print("qwe123".islower())  # True
print()

# isdigit()檢測字符串是否只由數(shù)字組成
print("1234".isdigit())  # True
print("1234asd".isdigit())  # False
print()

# istitle()檢測字符串中的首字母是否大寫
print("Hello World".istitle())  # True
print("hello every body".istitle())  # False
print()

# isalpha()檢測字符串是否只由字母和文字組成
print("你好everyone".isalpha())  # True
print("你好everyone123".isalpha())  # False

# 前綴和后綴:判斷字符串是否以指定字符開頭或者以指定字符結(jié)束

# startswith()判斷字符串是否以指定字符開頭
# endwith()判斷字符串是否以指定字符結(jié)束
s1 = "HelloPython"
print(s1.startswith("Hello"))  # True
print(s1.endswith("thon"))  # True

# encode()編碼
# decode()解碼
s2 = "hello py小王子"
print(s2.encode())  # b'hello py\xe5\xb0\x8f\xe7\x8e\x8b\xe5\xad\x90'
print(s2.encode("utf-8"))  # b'hello py\xe5\xb0\x8f\xe7\x8e\x8b\xe5\xad\x90'
print(s2.encode("gbk"))  # b'hello py\xd0\xa1\xcd\xf5\xd7\xd3'
# 解碼
s3 = b'hello py\xe5\xb0\x8f\xe7\x8e\x8b\xe5\xad\x90'
print(s3.decode())  # hello py小王子

print(chr(68))  # D
print(ord("a"))  # 97

# 字符串格式化輸出
'''
%占位符
%d表示整數(shù)
%f表示小數(shù)
%s表示字符串
%.3f(表示保留3位小數(shù),保留的小數(shù)數(shù)位自己可以控制)
'''
name = "py小王子"
sex = "男"
money = 198987932.787532
print("我的姓名是:%s" % name)  # 我的姓名是:py小王子
print("我的大號(hào)是%s,性別是%s,我的財(cái)富是%.2f" % (name, sex, money))
# 我的大號(hào)是py小王子,性別是男,我的財(cái)富是198987932.79
# 還可以通過f"{}{}"這種方式實(shí)現(xiàn)格式化輸出
print(f"我的大號(hào)是:{name},性別是:{sex},我的財(cái)富是{money}")  # 我的大號(hào)是:py小王子,性別是:男,我的財(cái)富是198987932.787532

s1 = 'hello, world'
print('wo' in s1)  # True
s2 = 'goodbye'
print(s2 in s1)  # False

s = 'hello, world'
# center方法以寬度20將字符串居中并在兩側(cè)填充*
print(s.center(20, '*'))  # ****hello, world****
# rjust方法以寬度20將字符串右對(duì)齊并在左側(cè)填充空格
print(s.rjust(20))  # hello, world
# ljust方法以寬度20將字符串左對(duì)齊并在右側(cè)填充~
print(s.ljust(20, '~'))  # hello, world~~~~~~~~
# 在字符串的左側(cè)補(bǔ)零
print('33'.zfill(5))  # 00033
print('-33'.zfill(5))  # -0033