python数据类型--字符串（一）

2018-6-11

一、字符串之capitalize

text = "abcd"
v = text.capitalize()
print(v)

输出：

<font color="#ff0000">"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
Abcd

Process finished with exit code 0</font>

text = "abcd"

v = text.capitalize()

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

Abcd

Process finished with exit code 0

参数：capitalize(self)

总结：capitalize将英文首字母改为大写字母

二、字符串之casefold

text = 'ABCcd'
v = text.casefold()
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
abccd

Process finished with exit code 0</font>

text = 'ABCcd'

v = text.casefold()

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

abccd

Process finished with exit code 0

参数: casefold(self)

总结：casefold将字符串中的大写字母转换为小写字母。

三、字符串之center

示例1：

text = 'ABCcd'
v = text.center(11)
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
   ABCcd   

Process finished with exit code 0</font>

text = 'ABCcd'

v = text.center(11)

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

ABCcd

Process finished with exit code 0

示例2：

text = 'ABCcd'
v = text.center(11,"*")
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
***ABCcd***

Process finished with exit code 0</font>

text = 'ABCcd'

v = text.center(11,"*")

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

***ABCcd***

Process finished with exit code 0

参数：center(self,width,fillchar=None)

总结：从以上两个示例中来看，字符串以center第一个（整型）参数为字符串长度进行居中，其它位默认以空格填充，如指定第二个参数（字符串参数），则以第二个参数填充。

四、字符串之count

示例1：

text = 'ABCcdcecd'
v = text.count('c')
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
3

Process finished with exit code 0</font>

text = 'ABCcdcecd'

v = text.count('c')

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

Process finished with exit code 0

示例2：

text = 'ABCcdcecd'
v = text.count('c',5)
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
2

Process finished with exit code 0</font>

text = 'ABCcdcecd'

v = text.count('c',5)

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

Process finished with exit code 0

示例3：

text = 'ABCcdcecd'
v = text.count('c',5,7)
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
1

Process finished with exit code 0</font>

text = 'ABCcdcecd'

v = text.count('c',5,7)

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

Process finished with exit code 0

参数：count(self,sub,start=None,end=None)

总结：从以上三个示例中看，count是查找字符串中存在第一个参数（区分大小写）的个数，第二个参数为查找的起始位置，第三个参数为查找的结束位置。

五、字符串之endswith

示例1：

text = 'ABCcdcecd'
v = text.endswith('cd')
print(v)

输出：

<font color="#ff0000">"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
True

Process finished with exit code 0</font>

text = 'ABCcdcecd'

v = text.endswith('cd')

print(v)

输出：

"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"

True

Process finished with exit code 0

示例2：

text = 'ABCcdcecd'
v = text.endswith('cd',3,5)
print(v)

输出：
<font color="#ff0000">
"D:\python\oldboy study\venv\Scripts\python.exe" "D:/python/oldboy study/S1.py"
True

Process finished with exit code 0</font>