python字符串常用操作字符串_python字符串常用操作
str1 = 'abc'
print(str1)
str2 = "sabc"
str3 = '''
a f
asdf
da
'''
print(str3)
abc
a f
asdf
da
#转义字符
print('\n\\')
\
#序列通用功能
print(str1)
print('a' in str1)
print(str1 + str2)
print(str1*3)
print(str1)
print(str1[2])
print(str1[-1])
print(str1.index('a'))
print(len(str1))
print(str1.count('a'))
print('字符串的长度',len(str1))
print('长度' + str(len(str1)))
abc
True
abcsabc
abcabcabc
abc
c
c
0
3
1
字符串的长度 3
长度3
# 字符串常用功能
#str.replace(old,new,count): 修改字符串，修改几个
st = 'im handsome'
st2 = st.replace('handsome','ugly')
print(st,st2)
st = 'hahahah'
st2 = st.replace('ha','he',2)
print(st,st2)
#str.split(obj): 拆分字符串，生成列表
st = 'poi01,116,446238,39.940166'
lst = st.split(',')
print(lst)
#st.join: 链接字符串，参数为列表
lst = ['poi01', '116', '446238', '39.940166']
m = '_'
st = m.join(lst)
print(st)
#str.startswith(str):判断是否以a开头
#str.endswith(str):
str = 'abafewwef'
print(str.startswith('a'))
print(str.endswith('f'))
print(str.upper(),str)
print(str.lower())
print(str.swapcase()) #大小写互换
print(str.capitalize()) #首字母大写
#判断是否为数字
st = '12333'
print(st.isnumeric())
#判断是否字符
st = 'adf'
print(st.isalpha())
#删除末尾的空格
st = 'avd '
print(st.rstrip())
im handsome im ugly
hahahah hehehah
['poi01', '116', '446238', '39.940166']
poi01_116_446238_39.940166
True
True
ABAFEWWEF abafewwef
abafewwef
ABAFEWWEF
Abafewwef
True
True
avd
#格式化字符串，字符串中输入变量
# %s表示插入一个变量(字符串)， %name插入name
name = 'fatbird'
truth = '%s is good' %name
print(truth)
x = 4
y = 'hehe'
z = 4.256
print('this is %i' %x)
print('this is %s' %y)
print('this is %0.2f' %z)
fatbird is good
this is 4
this is hehe
this is 4.26
#格式化字符串
m = 3.1554
print('pi is %f' %m)
print('pi is %.3f' %m) #四舍五入
m = 10.6
print('pi is %i' %m) #直接切掉小数部分
print('pi is %.0f' %m)
m = 100
print('%i' %m)
print('%+i' %m)
print('%.2f' %-0.01) #负号根据数字直接显示
m = 100
print('% i' %m)
print('% +i' %m)
print('% .2f' %-0.01)
m = 123.123123123
print('% 2e' %m)
print('% 4E' %m)
m = 12132134134523.1231231231213212313
m2 = 1.2
print('%g' %m)
print('%G' %m2)#小数位少的自动识别用浮点数，数据复杂的时候自动识别用科学计数法
pi is 3.155400
pi is 3.155
pi is 10
pi is 11
100
+100
-0.01
100
+100
-0.01
1.231231e+02
1.231231E+02
1.21321e+13
1.2
#格式化字符串 format
print('user id:{0}'.format('root'))
print('{}hehe{}'.format('a','b'))
print('{}{}{}'.format('a','b','c'),'\n','{0}{0}{0}{0}'.format('a','b','c'),'\n')
print('我的工作是{work}'.format(work='设计'))
x = 'abc{}'
a = x.format('def')
print(a,x)
print('{:f}'.format(4.123))
print('{:.2f}'.format(4.123))
print('{:e}'.format(4.123))
print('{:.0f}'.format(4.123))
print('{:%}'.format(4.123))
print('{:d}'.format(10))
user id:root
aheheb
abc
aaaa
我的工作是设计
abcdef abc{}
4.123000
4.12
4.123000e+00
4
412.300000%
10
print(33+int('22'))
m = 'a,a,b'
m.split()
55
['a,a,b']