day 10 21:00 21:49

Posted 2020-11-18 yikedashuyikexiaocao

str

小写

test="ABC"
v=test.lower()处理普通的 
.casefold()   更牛逼
print(v)//abc

test="ABC"
v=test.center(10,"%")
print(v)//%%%ABC%%%%

test="qABACs1A5A4"
v1=test.count("A")  找子序列中出现的个数
v2=test.count("A",5)
print(v1)
print(v2)//4  2

test="qABACs1A5A4"
v1=test.endswith("4")判断以什么开头结尾
v2=test.startswith("q")
print(v1)
print(v2)//True  True

test="Cs1A4s1"
#从开始往后找，找到第一个之后，获取其序列号
v1=test.find("s1")
v2=test.find("s1",3,10)
print(v1)
print(v2)//1 5

test="i am  {name},age {a}"
#格式化，将一个字符串中的占位符替换为指定的值
print(test)
v=test.format(name="alex",a=12)
print(v)//i am {name},age {a}  i am  alex,age 12

test="i am  {0},age {1}"
#按照顺序替换
print(test)
v=test.format("alex","233")
print(v)//i am {0},age {1}  i am  alex,age 233

test="i am  {a},age {b}"
#按照字典替换
print(test)
v=test.format_map({"a":"alex","b":"1"})
print(v)//i am {a},age {b}  i am  alex,age 1

#判断字符串是否只能是字母或者数字
test="d33"
v=test.isalnum()
print(v)//true