2. To Lower Case

Title：

Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase.

Example 1:

Input: "Hello"
Output: "hello"

Example 2:

Input: "here"
Output: "here"

Note:

None

Analysis of Title：

There is nothing to explain.

Test case：

"Hello"

Python：

class Solution(object):
　　def toLowerCase(self, str):
　　"""
　　:type str: str
　　:rtype: str
　　"""
　　res = ""
　　for c in str:
　　　　bse = ord(c)
　　　　if bse<91 and bse>64:
　　　　　　res+=chr(bse + 32)
　　　　else:
　　　　　　res+=c
　　return res

Analysis of Code：

1.ord()　　return the ASCII number

2.chr()　　return the ASCII char

3. (64,91)  This is the Capital letters’s range, A = 65, Z = 90

4. The capital letters add 32 equals Lowercase letters.

So, go through the str, if it‘s a capital, add 32, else it‘s a lowercase letters originally.

Notice: type(res)=str, and str+int=str, so "else:res+=c" is return str-type successful although c is int-type.

原文地址：https://www.cnblogs.com/sxuer/p/10628692.html