在本教程中，我们将学习如何使用Python的Prettytable模块创建关系表。我们将创建表格而无需使用外部库。

什么是Pretty Table？

漂亮的表格是数据的可视化呈现，采用表格形式的ASCII表格，易于使用。prettytable库包括PrettyTable类，用于创建关系表。要使用此库，需要使用以下命令进行安装。

安装

pip install prettytable

使用Pretty Table创建表格

在这里，我们将使用Pretty Table模块逐行创建表格。让我们理解以下示例。

示例 - 1： 逐行创建表格

from prettytable import PrettyTable  
  
# Creating a new table   
newTable = PrettyTable(["Student Name", "Class", "Subject", "Makrs"])  
  
# Add rows  
newTable.add_row(["Camron", "X", "English", "91"])  
newTable.add_row(["Haris", "X", "Math", "63"])  
newTable.add_row(["Jenny", "X", "Science", "90"])  
newTable.add_row(["Bernald", "X", "Art", "92"])  
newTable.add_row(["Jackson", "X", "Science", "98"])  
newTable.add_row(["Samual", "X", "English", "88"])  
newTable.add_row(["Stark", "X", "English", "95"])  
  
print(newTable)

输出：

+--------------+-------+---------+-------+
| Student Name | Class | Subject | Makrs |
+--------------+-------+---------+-------+
|    Camron    |   X   | English |   91  |
|    Haris     |   X   |   Math  |   63  |
|    Jenny     |   X   | Science |   90  |
|   Bernald    |   X   |   Art   |   92  |
|   Jackson    |   X   | Science |   98  |
|    Samual    |   X   | English |   88  |
|    Stark     |   X   | English |   95  |
+--------------+-------+---------+-------+

示例 - 2： 列方式创建表格

from prettytable import PrettyTable  
  
columns = ["Student Name", "Class", "Subject", "Marks"]  
  
newTable = PrettyTable()  
  
# Add Columns  
newTable.add_column(columns[0], ["Jacob", "Peter", "Grenger",  
                    "Stark", "Falcon", "Matthew", "Jackson"])  
newTable.add_column(columns[1], ["X", "X", "X", "X", "X", "X", "X"])  
newTable.add_column(columns[2], ["English", "Art", "Science", "Math", "Science", "English", "English"])  
newTable.add_column(columns[3], ["91", "63", "90", "92",  
                                        "98", "83", "95"])  
  
print(newTable)

输出：

+--------------+-------+---------+-------------------+
| Student Name | Class | Subject | Marks |
+--------------+-------+---------+-------------------+
|    Jacob             |   X     | English |   91    |
|    Peter             |   X     |   Art   |   63    |
|   Grenger            |   X     | Science |   90    |
|    Stark             |   X     |   Math  |   92    |
|    Falcon            |   X     | Science |   98    |
|   Matthew            |   X     | English |   83    |
|   Jackson            |   X     | English |   95    |
+--------------+-------+---------+------------------+

我们使用了prettytable模块的add_column()方法。

示例 - 3： 一次添加多行

from prettytable import PrettyTable  
  
# Creating a new table  
newTable = PrettyTable(["Student Name", "Class", "Subject", "Makrs"])  
  
# # Add rows  
newTable.add_rows(   
    [  
        ["Camron", "X", "English", "91"],  
        ["Haris", "X", "Math", "63"],  
        ["Jenny", "X", "Science", "90"],  
        ["Bernald", "X", "Art", "92"],  
        ["Jackson", "X", "Science", "98"],  
        ["Samual", "X", "English", "88"],  
        ["Stark", "X", "English", "95"],  
  
    ]  
)  
  
print(newTable)

输出：

+--------------+-------+---------+-------+
|    Camron    |   X   | English |   91  |
|    Haris     |   X   |   Math  |   63  |
|    Jenny     |   X   | Science |   90  |
|   Bernald    |   X   |   Art   |   92  |
|   Jackson    |   X   | Science |   98  |
|    Samual    |   X   | English |   88  |
|    Stark     |   X   | English |   95  |
+--------------+-------+---------+-------+

PrettyTable 删除行

此模块提供了del_row()方法，用于删除行。它接受要删除的行的索引值并将其从表格中删除。索引从零开始。让我们了解以下代码。

示例：

from prettytable import PrettyTable  
  
# Creating a new table  
newTable = PrettyTable(["Student Name", "Class", "Subject", "Makrs"])  
  
# # Add rows  
newTable.add_row(["Camron", "X", "English", "91"])  
newTable.add_row(["Haris", "X", "Math", "63"])  
newTable.add_row(["Jenny", "X", "Science", "90"])  
newTable.add_row(["Bernald", "X", "Art", "92"])  
newTable.add_row(["Jackson", "X", "Science", "98"])  
newTable.add_row(["Samual", "X", "English", "88"])  
newTable.add_row(["Stark", "X", "English", "95"])  
  
newTable.del_row(1)  
newTable.del_row(2)  
newTable.del_row(3)  
  
print(newTable)

输出：

+--------------+-------+---------+-------+
| Student Name | Class | Subject | Makrs |
+--------------+-------+---------+-------+
|    Camron          |   X   | English |   91   |
|    Jenny               |   X   | Science |   90  |
|   Jackson            |   X   | Science |   98  |
|    Stark                |   X   | English |   95  |
+--------------+-------+---------+-------+

它将从表格中删除特定的行。要清除整个表格，我们使用以下方法：

myTable.clear_rows()

示例 - 2：

from prettytable import PrettyTable  
  
# Creating a new table  
newTable = PrettyTable(["Student Name", "Class", "Subject", "Makrs"])  
  
# # Add rows  
newTable.add_row(["Camron", "X", "English", "91"])  
newTable.add_row(["Haris", "X", "Math", "63"])  
newTable.add_row(["Jenny", "X", "Science", "90"])  
newTable.add_row(["Bernald", "X", "Art", "92"])  
newTable.add_row(["Jackson", "X", "Science", "98"])  
newTable.add_row(["Samual", "X", "English", "88"])  
newTable.add_row(["Stark", "X", "English", "95"])  
  
newTable.clear_rows()  
  
print(newTable)

输出：

+--------------+-------+---------+------------------+
| Student Name | Class | Subject | Makrs |
+--------------+-------+---------+--------------------+
+--------------+-------+---------+--------------------+

正如我们在上面的代码中看到的，所有行都已被删除。我们只能看到列名。

获取特定的行和列

prettytable的主要目的是以ASCII形式获得表格。我们可以使用以下方法限制表格的输出。

get_string(fields=["Column 1", "Column2", .............., ColumnN]

让我们了解以下示例。

示例：

from prettytable import PrettyTable  
  
# Creating a new table  
newTable = PrettyTable(["Student Name", "Class", "Subject", "Makrs"])  
  
# # Add rows  
newTable.add_rows(   
    [  
        ["Camron", "X", "English", "91"],  
        ["Haris", "X", "Math", "63"],  
        ["Jenny", "X", "Science", "90"],  
        ["Bernald", "X", "Art", "92"],  
        ["Jackson", "X", "Science", "98"],  
        ["Samual", "X", "English", "88"],  
        ["Stark", "X", "English", "95"],  
  
    ]  
)  
  
print(newTable.get_string(fields=["Student Name", "Class"]))

输出：

+--------------+--------------+
| Student Name | Class |
+--------------+--------------+
|    Camron          |   X   |
|    Haris               |   X   |
|    Jenny               |   X   |
|   Bernald            |   X   |
|   Jackson            |   X   |
|    Samual            |   X   |
|    Stark                |   X   |
+--------------+---------------+

字段参数接受要打印的字段名称列表。

我们还可以使用以下方法来控制结果：

print(newTable.get_string(start=1, end=4)

输出：

+--------------+-------+---------+-------------------+
| Student Name | Class | Subject | Makrs |
+--------------+-------+---------+-------------------+
|    Camron          |   X   | English |   91  |
|    Haris               |   X   |   Math  |   63  |
|    Jenny             |   X   | Science |   90  |
+--------------+-------+---------+------------------+

更改列的对齐方式

我们可以观察到表格中的所有列都居中对齐。我们可以根据需要将其更改为align属性分配一个字符，有三个字符串 - 'l'（左对齐），'r'（右对齐）和'c'（居中对齐）。

让我们看以下示例。

示例 -

newTable.align = 'r'  
print(newTable)

输出：

+--------------+-------+---------+-------------------+
| Student Name | Class | Subject | Makrs |
+--------------+-------+---------+------------------+
|           Camron |     X | English |    91  |
|             Haris  |     X |    Math |    63 |
|             Jenny |     X | Science |    90 |
|            Bernald |     X |     Art |    92 |
|           Jackson |     X | Science |    98 |
|           Samual  |     X | English |    88 |
|            Stark     |     X | English |    95 |
+--------------+-------+---------+------------------+

更改表格的外观

默认表格看起来像SQL数据库界面。然而，我们可以将表格外观修改为其他格式。prettytable模块提供了set_style()方法，将表格变成适合MS Word的友好格式。

让我们看以下示例。

示例 - 将以下代码添加到创建表格代码中。

from prettytable import MSWORD_FRIENDLY  
  
newTable.set_style(MSWORD_FRIENDLY)  
print(newTable)

输出：

| Student Name | Class | Subject | Makrs |
|    Camron         |   X   | English   |       91  |
|    Haris              |   X   |   Math     |   63  |
|    Jenny              |   X   | Science   |   90  |
|   Bernald           |   X   |   Art         |   92  |
|   Jackson           |   X   | Science   |   98  |
|    Samual           |   X   | English   |   88  |
|    Stark               |   X   | English   |   95  |

我们可以清楚地看到默认表格和MS Word友好表格之间的区别。

结论

我们已经讨论了在使用Python脚本工作时，使用prettytable模块执行一些重要操作。这是一个非常有效的模块，用于处理表格。

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