day1/作业

作业题

 1 name = 'alex'
 2 print(name.strip())
 3 print(name.startswith('a1'))
 4 print(name.endswith('X'))
 5 print(name.replace('1','p'))
 6 print(name.split('1'))
 7 print(name.upper())
 8 print(name.lower())
 9 print(name[1])
10 print(name[0:3])
11 print(name[-2:])
12 print(name.find('e'))
13 print(name[0:len(name)-1])

上课笔记

# 字符串的操作
str1 = 'my name is xxx,my age is 18.'去
# 1.优先掌握的操作：
# 按索引取值（正向取，反向取）：只能取
print(str1[3])
# 2.切片（顾头不顾尾，步长）
print(str1[3:7])
# 步长为2
print(str1[3:10:2])
# 3.长度len
print(len(str1))
# 4.成员运算in和not in
print('x' in str1)
print('Y' in str1)

# 5.切分split
# 会根据split()括号中的规则去切分字符串，然后把每一个值追加到列表中
str2 = 'my name is xxx,my age is 18.'
list2 = str2.split(' ')
print(list2)
# 6.移除空白strip
#去除字符串左右两边的空格
str1 = 'my name is xxx,my age is 18.'
print(str1)
print(str1.strip())
# 7.循环
str2 = 'my name is xxx,my age is 18.'
for line in str2:
    print(line)             # print默认参数enf="\n"
    print(line,end=" ")     #自定义参数
# 需要掌握的
str4 = 'my name is xxx,my age is 18.'
str5 = 'my name is xxx,my age is 18.'
# 1.strip,lstrip,rstrio
# l去除左边的空格或者指定符号
# r去除右边的空格或者指定符号
print(str4.lstrip())
print(str5.rstrip())
str4= '***my name is xxx,my age is 18.'
str5 = 'my name is xxx,my age is 18.***'
print(str4.lstrip('*'))
print(str5.rstrip('*'))
# 2.lower（转换成小写），upper（转换成大写）
str6 = 'mw name is Cc'
print(str6.lower())
print(str6.upper())
# 3.startswith,endswith(判断字符串首位是否成立)
print(str6.startswith("my"))
print(str6.startswith("MY"))
print(str6.endswith("Cc"))
print(str6.endswith("cc"))
# 4.format的四种玩法
# 方式一：按位置替换
str7 = 'my name is {},my age is {}'
str7 = str7.format('cc',18)
print(str7)
# 方式二： 按照索引替换
str7 = 'my name is {0},my age is {1}'
str7 = str7.format('cc',18,111)
print(str7)
# 方式三：指名道姓替换
str7 = 'my name is {name},my age is {age}'
str7 = str7.format(age=18,name='cc')
print(str7)
# 6.join
# 字符串拼接，会对列表中的数据按照某种标识进行拼接
name = 'cc'
age = "18"
print(':'.join([name,age]))
# sex = 1
# print(':').join([name,age])
# 报错expected str instance,int found
# print(':'.join([name,age,sex]))
# 7. replace
srt8 = 'old new'
# 括号中第一个参数是旧参数，第二个是新参数
str8 = srt8.replace('old','python')
print(str8)
# 8.循环
list1 = {'cc',18,'male',3.0,9}
for line in list1:
    print(line)