list循环 字典循环 字符串常用方法

list = ['xiaoli','xiaohua','huali']
user = {'zhang':'123','lin':'321','chen':'222'}
#list循环
for stu in list:
    print('循环的值',stu)

#字典循环
for stu in user:
    sql = 'inset into users(username,paw) value (%s,%s);'%(stu,user[stu])
    print(sql)
for stu in user:
    print('k==>',stu)
    print('value==>',user[stu])
for key,value in user.items():
    print('%s => %s'%(key,value))

#字符串常用操作

name = 'xiaoli'
#找下标
print(name.index('i'))
print(name.find('i'))
#index find 区别

print(name.find('z'))
#print(name.index('z'))  #index 查找没有的元素会报错


mima = '  1 2 1  '
print(mima)
#去除字符串前后的空格和换行符
print(mima.strip())
#去除字符串左边的空格
print(mima.lstrip())
#去除字符串右边的空格
print(mima.rstrip())
#替换字符 可用于去除空格
print(mima.replace(' ',''))
print(mima.replace('1',''))
image = 'x.jpg'
#判断是否是以***开始
print(name.startswith('xi'))
#判断是否是以***结束
print(image.endswith('.jpg'))
#判断是否为整数
s = '123'
print(s.isdigit())
#判断字符串是否全为小写
s1 = 'sdfS``'
print(s1.islower())
print(s1.isupper())
#判断是否为空
s2 = '    '
print(s2.isspace())
#判断字符串里是否有特殊字符 若存在特殊字符结果为false
s3 = 'lskdjf）234'
print(s3.isalnum())
#是否全为字母
print(s1.isalpha())
#首字母大写
print(s3.capitalize())
print(s.capitalize())
#用0补齐数字的站位  例如三位数，若数字为9 则补0后则为 009
i = '9'
print(i.zfill(3))
#
name = 'Hello World'
#转换为大写
print(name.upper())
#转换为小写
print(name.lower())

#将字符串中的值单独提出
stu = 'xiaoming,xiaoli,liming'
names = stu.split(',')
print(names)
#连接 join函数只适用于字符串类型
print(','.join(names))
num = '123'
print(' '.join(num))

#字符串可进行加法及乘法

n1 = 'x1'
n2 = 'x2'
n3 = n1+n2
n4 = n1 * 3
print(n4)
print(n3)