- 学习测试开发的Day85，真棒！
- 学习时间为1H20M
- 第八次全天课(下午视频3H15M-4H03M_END）
改写lower()
代码：
def lower(s):
if not isinstance(s,str):
return s
result=""
for i in s:
if (i>="A" and i<="Z"):
result+=chr(ord(i)+32)
else:
result+=i
return result
print(lower("我们124sdfRTYUI"))
输出：
PS D:\0grory\day8> python .\mylower.py
我们124sdfrtyui
PS D:\0grory\day8>
改写isletter()
算法：
判断所有的字符串，判断是否有一个不是字母，有一个不是就返回False，函数执行结束
代码：
def isletter(s):
if not isinstance(s,str):
return False
for i in s:
if not ((i>="a" and i <="z") or (i>="A" and i<="Z")):
return False
return True
print(isletter("asdf"))
print(isletter("A士大夫"))
print(isletter(23423))
print(isletter("FGHsdf"))
输出：
PS D:\0grory\day8> python .\myletter.py
True
False
False
True
PS D:\0grory\day8>
判断是否是大写字母 is_upper_letter()
代码：
def is_upper_letter(s):
if not isinstance(s,str):
return False
for i in s:
if not (i>="A" and i<="Z"):
return False
return True
print(is_upper_letter("ASDFG"))
print(is_upper_letter("asdf"))
print(is_upper_letter("A士大夫"))
print(is_upper_letter(23423))
print(is_upper_letter("FGHsdf"))
输出：
PS D:\0grory\day8> python .\my_upper_letter.py
True
False
False
False
False
PS D:\0grory\day8>
判断是否是小写字母 is_lower_letter()
代码：
def is_lower_letter(s):
if not isinstance(s,str):
return False
for i in s:
if not (i>="a" and i<="z"):
return False
return True
print(is_lower_letter("ASDFG"))
print(is_lower_letter("asdf"))
print(is_lower_letter("A士大夫"))
print(is_lower_letter(23423))
print(is_lower_letter("FGHsdf"))
输出：
PS D:\0grory\day8> python .\my_lower_letter.py
False
True
False
False
False
PS D:\0grory\day8>
判断是否是字母+数字，改写is_alpnum()
代码：
def is_alpnum(s):
if not isinstance(s,str):
return False
for i in s:
if not ((i>="a" and i <="z") or (i>="A" and i<="Z") or (i>='0' and i<='9')):
return False
return True
print(is_alpnum("asdf"))
print(is_alpnum("A士大夫"))
print(is_alpnum("23423"))
print(is_alpnum("FGHsdf"))
输出：
PS D:\0grory\day8> python .\my_alpnum.py
True
False
True
True
PS D:\0grory\day8>
改写find
版本1
代码：
def find(s,w):
if not (isinstance(s,str) and isinstance(w,str)):
return -1
for i in range(len(s)):
if s[i:i+len(w)]==w:
return i
print(find("sadf","d"))
输出：
PS D:\0grory\day8> python .\my_find.py
2
PS D:\0grory\day8>
版本2
代码:
def find(s,w,start=None,end=None):
if not (isinstance(s,str) and isinstance(w,str)):
return -1
if start is None:
start=0
if end is None:
end=len(s)
if not (isinstance(start,int) and isinstance(end,int)):
return -1
for i in range(len(s))[start:end]:
if i+len(w)>=end+1:
return -1
if s[i:i+len(w)]==w:
return i
return -1
print(find("sadf","a"))
print(find("sadf","d",0,6))
print(find("sadf","df",0,4))
print(find("sadf","f",0,4))
输出:
PS D:\0grory\day8> python .\my_find.py
1
2
2
3
PS D:\0grory\day8>
>>> list(range(10)[3:1:-1])
[3, 2]
>>> list(range(10)[3:1])
[]
>>>
可以尝试下 replace、split
>>> a="abcdabcdabcd"
>>> a=list(a)
>>> a
['a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd']
>>> [1,1,1,1,c,d,1,1,1,1,c,d.....]
切片是可以超过范围的
>>> [1,2,3][1:8]
[2, 3]
>>> [1,2,3][11:18]
[]
>>>
