Python基础

class: center, middle, inverse, title-slide

# Python基础
## 🌱
### 吴燕丰
### 江西财大，金融学院
### 2020/09/17

---

### 标准数据类型

.pull-left[
不可变数据（immutable）:
- Number(数字)
- String(字符串)
- Tuple(元组)
]

--
.pull-right[
可变数据（mutable）:
- List(列表)
- Dictionary(字典)
- Set(集合)
]

---

### Number(数字)

```python
a, b, c, d = 20, 5.5, True, 4+3j
print(type(a), type(b), type(c), type(d))
```

```
## <class 'int'> <class 'float'> <class 'bool'> <class 'complex'>
```

.pull-left[

```python
5 + 5
```

```
## 10
```

```python
4.3 - 2
```

```
## 2.3
```

```python
3 * 7
```

```
## 21
```

```python
2 / 4
```

```
## 0.5
```
]

.pull-right[

```python
2 // 4
```

```
## 0
```

```python
17 % 3
```

```
## 2
```

```python
2 ** 5
```

```
## 32
```
]

---

### String(字符串)

```python
str = 'JXUFE'
print(str); print(str[0:-1])
```

```
## JXUFE
## JXUF
```

```python
print(str[0]); print(str[2:])
```

```
## J
## UFE
```

```python
print(str * 2); print(str + ' School of Finance')
```

```
## JXUFEJXUFE
## JXUFE School of Finance
```

---

### Tuple(元组)

```python
tuple = (1, 'two', '三')
print(tuple); print(tuple[0])
```

```
## (1, 'two', '三')
## 1
```

```python
print(tuple[:1]); print(tuple[1:])
```

```
## (1,)
## ('two', '三')
```

```python
print(tuple * 2); print(tuple + tuple)
```

```
## (1, 'two', '三', 1, 'two', '三')
## (1, 'two', '三', 1, 'two', '三')
```

<hr>

修改元组元素的操作是非法的

```python
tuple = (1, 'two', '三')
tuple[0] = 100
```

---

### list(列表)

![](./images/list.jpg)

**左闭右开**：[n, m)

.footnote[
图片来源：https://www.runoob.com/python3/python3-data-type.html
]

---

### Dictionary(字典)

```python
dict = {}
dict['姓'] = '吴'
dict['名'] = '燕丰'

d2 = {'author': 'Yanfeng Wu', 'site': 'www.upjian.com'}

print('姓: ' + dict['姓'] +'；名: '+ dict['名'])
```

```
## 姓: 吴；名: 燕丰
```

```python
print(d2)
```

```
## {'author': 'Yanfeng Wu', 'site': 'www.upjian.com'}
```

```python
print(d2.keys())
```

```
## dict_keys(['author', 'site'])
```

```python
print(d2.values())
```

```
## dict_values(['Yanfeng Wu', 'www.upjian.com'])
```

---

### Set(集合)

```python
A = set('abcd'); B = {'c', 'd', 'e', 'f'}
print(A); print(B)
```

```
## {'a', 'b', 'c', 'd'}
## {'f', 'e', 'c', 'd'}
```

```python
print(A - B)
```

```
## {'a', 'b'}
```

```python
print(A & B)
```

```
## {'c', 'd'}
```

```python
print(A ^ B)
```

```
## {'e', 'a', 'b', 'f'}
```

---

### 字符串的内建函数（built-in）函数

.pull-left[
- capitalize()
- center(width, fillchar)
- count(str, beg=0, end=len(string))
- isdigit();
isalpha()
- join(seq)
- replace(old, new [, max])
- split(str="", num=string.count(str))
- splitlines([keepends])
- zfill (width)
- isdecimal()
]

.pull-right[
- find(str, beg=0, end=len(string)); 	
rfind(str, beg=0,end=len(string))
- ljust(width[, fillchar]);	
rjust(width,[, fillchar])
- lstrip(); 
rstrip(); 
strip([chars])
- endswith(suffix, beg=0, end=len(string)); 
startswith(substr, beg=0,end=len(string))
- maketrans()
- translate(table, deletechars="")
]

```python
'JXUFE'.center(40, '♠')
```

```
## '♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠JXUFE♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠♠'
```

```python
'♣'.join(['J','X','U','F','E'])
```

```
## 'J♣X♣U♣F♣E'
```

---

### 作业一

**最后一个单词的长度**：
请写代码计算出
[顺丰控股2019年年度报告（英文版）.PDF](https://www.sf-express.com/cn/sc/download/20200701-IR-EN-2019-2.PDF) 第12页文本中最后一个单词的长度。

[作业一素材.txt](作业一素材.txt)

注意：不考虑页脚内容（顺丰控股股份有限公司 S.F. HOLDING CO., LTD.）

---

### 作业一 附加题

**最后一个句子的长度**(附加题，选做)：
请写代码计算出
[顺丰控股2019年年度报告.PDF](https://www.sf-express.com/cn/sc/download/20200324-IR-RPT-1-2019.PDF) 第13页文本中最后一个句子的长度。

[作业一附加选做题素材.txt](作业一附加选做题素材.txt)

注意：不考虑页脚内容（顺丰控股股份有限公司 S.F. HOLDING CO., LTD.）

### 使用open()函数

**提示：**可使用如下代码将文本读入内存：

```python
# 须先将素材文件打开并保存至代码文件夹

f = open('作业一附加选做题素材.txt', 'w', encoding='utf-8')
txt = f.read()
f.close()
```

.footnote[
如果运行报错，见
[解决方案](../../application/current_working_dir_explained/current_working_dir_explained.html#2)。
]
---

### Just Code It

.pull-left[
![Just Do It](./images/justdoit.png)
]

.pull-right[
![](./images/justcodeit.png)
]