{"id":1073889,"date":"2025-01-08T11:29:38","date_gmt":"2025-01-08T03:29:38","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1073889.html"},"modified":"2025-01-08T11:29:40","modified_gmt":"2025-01-08T03:29:40","slug":"python%e5%a6%82%e4%bd%95%e7%94%a8%e5%88%97%e5%90%8d%e5%bc%95%e7%94%a8%e6%95%b0%e6%8d%ae%e7%b1%bb%e5%9e%8b-2","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1073889.html","title":{"rendered":"python\u5982\u4f55\u7528\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b"},"content":{"rendered":"

\"python\u5982\u4f55\u7528\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b\"<\/p>\n

\u5728Python\u4e2d\uff0c\u4f7f\u7528\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b\u7684\u5e38\u89c1\u65b9\u5f0f\u5305\u62ec\uff1a\u4f7f\u7528Pandas\u5e93\u3001\u4f7f\u7528CSV\u6a21\u5757\u3001\u4f7f\u7528SQLAlchemy\u5e93\u3001\u7ed3\u5408NumPy\u5e93\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u8fd9\u51e0\u79cd\u65b9\u6cd5\u7684\u5e94\u7528\u548c\u5b9e\u73b0\u3002<\/strong><\/p>\n<\/p>\n

\u4e00\u3001Pandas\u5e93<\/h3>\n<\/p>\n

Pandas\u662fPython\u4e2d\u6700\u5e38\u7528\u7684\u6570\u636e\u5206\u6790\u5e93\u4e4b\u4e00\u3002\u5b83\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684\u6570\u636e\u7ed3\u6784\u548c\u6570\u636e\u5206\u6790\u5de5\u5177\uff0c\u5176\u4e2d\u6700\u91cd\u8981\u7684\u6570\u636e\u7ed3\u6784\u662fDataFrame\u3002DataFrame\u662f\u4e00\u4e2a\u4e8c\u7ef4\u7684\u8868\u683c\u6570\u636e\u7ed3\u6784\uff0c\u7c7b\u4f3c\u4e8eExcel\u8868\u683c\u6216SQL\u8868\u683c\u3002\u901a\u8fc7\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b\u5728Pandas\u4e2d\u975e\u5e38\u7b80\u5355\u3002<\/p>\n<\/p>\n

1.1 \u521b\u5efaDataFrame<\/h4>\n<\/p>\n

\u9996\u5148\uff0c\u6211\u4eec\u9700\u8981\u521b\u5efa\u4e00\u4e2aDataFrame\u3002\u53ef\u4ee5\u901a\u8fc7\u4eceCSV\u6587\u4ef6\u8bfb\u53d6\u6570\u636e\u6765\u521b\u5efaDataFrame\uff0c\u4e5f\u53ef\u4ee5\u76f4\u63a5\u4ece\u5b57\u5178\u6216\u5217\u8868\u521b\u5efa\u3002<\/p>\n<\/p>\n

import pandas as pd<\/p>\n
\u4ece\u5b57\u5178\u521b\u5efaDataFrame<\/strong><\/h2>\n
data = {<\/p>\n
    'Name': ['Alice', 'Bob', 'Charlie'],<\/p>\n
    'Age': [25, 30, 35],<\/p>\n
    'Salary': [50000, 60000, 70000]<\/p>\n
}<\/p>\n
df = pd.DataFrame(data)<\/p>\n
print(df)<\/p>\n
<\/code><\/pre>\n<\/p>\n
1.2 \u5f15\u7528\u5217\u540d<\/h4>\n<\/p>\n
\u5f15\u7528\u5217\u540d\u975e\u5e38\u7b80\u5355\uff0c\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u5217\u540d\u4f5c\u4e3aDataFrame\u7684\u952e\u6765\u8bbf\u95ee\u5217\u6570\u636e\u3002<\/p>\n<\/p>\n
# \u5f15\u7528\u5217\u540d<\/p>\n
age_column = df['Age']<\/p>\n
print(age_column)<\/p>\n
<\/code><\/pre>\n<\/p>\n
1.3 \u64cd\u4f5c\u5217\u6570\u636e<\/h4>\n<\/p>\n
\u53ef\u4ee5\u5bf9\u5f15\u7528\u7684\u5217\u6570\u636e\u8fdb\u884c\u5404\u79cd\u64cd\u4f5c\uff0c\u4f8b\u5982\u8ba1\u7b97\u5e73\u5747\u503c\u3001\u6700\u5927\u503c\u3001\u6700\u5c0f\u503c\u7b49\u3002<\/p>\n<\/p>\n
# \u8ba1\u7b97\u5e73\u5747\u5e74\u9f84<\/p>\n
average_age = df['Age'].mean()<\/p>\n
print("Average Age:", average_age)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e8c\u3001CSV\u6a21\u5757<\/h3>\n<\/p>\n
CSV\u6a21\u5757\u662fPython\u6807\u51c6\u5e93\u7684\u4e00\u90e8\u5206\uff0c\u7528\u4e8e\u8bfb\u53d6\u548c\u5199\u5165CSV\u6587\u4ef6\u3002\u867d\u7136CSV\u6a21\u5757\u4e0d\u5982Pandas\u5f3a\u5927\uff0c\u4f46\u5b83\u8db3\u591f\u7b80\u5355\u548c\u9ad8\u6548\uff0c\u9002\u5408\u5904\u7406\u5c0f\u578b\u6570\u636e\u96c6\u3002<\/p>\n<\/p>\n
2.1 \u8bfb\u53d6CSV\u6587\u4ef6<\/h4>\n<\/p>\n
import csv<\/p>\n
\u8bfb\u53d6CSV\u6587\u4ef6<\/strong><\/h2>\n
with open('data.csv', mode='r') as file:<\/p>\n
    csv_reader = csv.DictReader(file)<\/p>\n
    for row in csv_reader:<\/p>\n
        print(row)<\/p>\n
<\/code><\/pre>\n<\/p>\n
2.2 \u5f15\u7528\u5217\u540d<\/h4>\n<\/p>\n
\u5728CSV\u6a21\u5757\u4e2d\uff0c\u6570\u636e\u88ab\u8bfb\u53d6\u4e3a\u5b57\u5178\uff0c\u53ef\u4ee5\u901a\u8fc7\u5217\u540d\u6765\u5f15\u7528\u6570\u636e\u3002<\/p>\n<\/p>\n
# \u5f15\u7528\u5217\u540d<\/p>\n
with open('data.csv', mode='r') as file:<\/p>\n
    csv_reader = csv.DictReader(file)<\/p>\n
    for row in csv_reader:<\/p>\n
        print(row['Age'])<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001SQLAlchemy\u5e93<\/h3>\n<\/p>\n
SQLAlchemy\u662fPython\u7684SQL\u5de5\u5177\u5305\u548c\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04\uff08ORM\uff09\u5e93\u3002\u5b83\u63d0\u4f9b\u4e86\u4e0e\u6570\u636e\u5e93\u4ea4\u4e92\u7684\u9ad8\u7ea7\u63a5\u53e3\uff0c\u53ef\u4ee5\u8f7b\u677e\u5730\u5f15\u7528\u5217\u540d\u3002<\/p>\n<\/p>\n
3.1 \u521b\u5efa\u6570\u636e\u5e93\u8fde\u63a5<\/h4>\n<\/p>\n
from sqlalchemy import create_engine, MetaData, Table<\/p>\n
\u521b\u5efa\u6570\u636e\u5e93\u8fde\u63a5<\/strong><\/h2>\n
engine = create_engine('sqlite:\/\/\/example.db')<\/p>\n
connection = engine.connect()<\/p>\n
metadata = MetaData()<\/p>\n
<\/code><\/pre>\n<\/p>\n
3.2 \u5f15\u7528\u5217\u540d<\/h4>\n<\/p>\n
# \u5f15\u7528\u5217\u540d<\/p>\n
table = Table('employees', metadata, autoload=True, autoload_with=engine)<\/p>\n
columns = table.columns.keys()<\/p>\n
print(columns)<\/p>\n
\u67e5\u8be2\u6570\u636e<\/strong><\/h2>\n
query = table.select()<\/p>\n
result = connection.execute(query)<\/p>\n
for row in result:<\/p>\n
    print(row['Age'])<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001NumPy\u5e93<\/h3>\n<\/p>\n
NumPy\u662fPython\u7684\u79d1\u5b66\u8ba1\u7b97\u5e93\uff0c\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684\u6570\u7ec4\u5bf9\u8c61\u548c\u5404\u79cd\u6570\u5b66\u51fd\u6570\u3002\u867d\u7136NumPy\u4e0d\u76f4\u63a5\u652f\u6301\u5217\u540d\u5f15\u7528\uff0c\u4f46\u53ef\u4ee5\u7ed3\u5408Pandas\u4f7f\u7528\u3002<\/p>\n<\/p>\n
4.1 \u521b\u5efaNumPy\u6570\u7ec4<\/h4>\n<\/p>\n
import numpy as np<\/p>\n
\u521b\u5efaNumPy\u6570\u7ec4<\/strong><\/h2>\n
data = np.array([<\/p>\n
    ['Alice', 25, 50000],<\/p>\n
    ['Bob', 30, 60000],<\/p>\n
    ['Charlie', 35, 70000]<\/p>\n
])<\/p>\n
\u5b9a\u4e49\u5217\u540d<\/strong><\/h2>\n
columns = ['Name', 'Age', 'Salary']<\/p>\n
<\/code><\/pre>\n<\/p>\n
4.2 \u5f15\u7528\u5217\u540d<\/h4>\n<\/p>\n
\u53ef\u4ee5\u901a\u8fc7\u5217\u7d22\u5f15\u6765\u5f15\u7528\u6570\u636e\uff0c\u7136\u540e\u7ed3\u5408\u5217\u540d\u8fdb\u884c\u64cd\u4f5c\u3002<\/p>\n<\/p>\n
# \u5f15\u7528\u5217\u540d<\/p>\n
age_column = data[:, columns.index('Age')]<\/p>\n
print(age_column)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u7ed3\u5408Pandas\u548cNumPy<\/h3>\n<\/p>\n
Pandas\u548cNumPy\u7684\u7ed3\u5408\u4f7f\u7528\u53ef\u4ee5\u53d1\u6325\u5404\u81ea\u7684\u4f18\u52bf\uff0c\u5b9e\u73b0\u66f4\u5f3a\u5927\u7684\u6570\u636e\u5904\u7406\u548c\u5206\u6790\u529f\u80fd\u3002<\/p>\n<\/p>\n
5.1 \u4eceNumPy\u6570\u7ec4\u521b\u5efaDataFrame<\/h4>\n<\/p>\n
# \u4eceNumPy\u6570\u7ec4\u521b\u5efaDataFrame<\/p>\n
df = pd.DataFrame(data, columns=columns)<\/p>\n
print(df)<\/p>\n
<\/code><\/pre>\n<\/p>\n
5.2 \u5f15\u7528\u5217\u540d\u5e76\u8fdb\u884c\u64cd\u4f5c<\/h4>\n<\/p>\n
# \u5f15\u7528\u5217\u540d\u5e76\u8fdb\u884c\u64cd\u4f5c<\/p>\n
average_salary = df['Salary'].astype(int).mean()<\/p>\n
print("Average Salary:", average_salary)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001\u603b\u7ed3<\/h3>\n<\/p>\n
\u5728Python\u4e2d\uff0c\u4f7f\u7528\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b\u7684\u65b9\u6cd5\u591a\u79cd\u591a\u6837\uff0c\u6700\u5e38\u7528\u7684\u65b9\u5f0f\u662f\u5229\u7528Pandas\u5e93\u3002Pandas\u63d0\u4f9b\u4e86\u5f3a\u5927\u4e14\u7075\u6d3b\u7684\u6570\u636e\u7ed3\u6784\u548c\u6570\u636e\u5206\u6790\u5de5\u5177\uff0c\u4f7f\u5f97\u5f15\u7528\u5217\u540d\u548c\u64cd\u4f5c\u6570\u636e\u53d8\u5f97\u975e\u5e38\u7b80\u5355\u548c\u9ad8\u6548\u3002\u5bf9\u4e8e\u5c0f\u578b\u6570\u636e\u96c6\uff0c\u53ef\u4ee5\u4f7f\u7528CSV\u6a21\u5757\uff1b\u5bf9\u4e8e\u6570\u636e\u5e93\u64cd\u4f5c\uff0c\u53ef\u4ee5\u4f7f\u7528SQLAlchemy\u5e93\uff1b\u7ed3\u5408NumPy\u548cPandas\uff0c\u53ef\u4ee5\u5b9e\u73b0\u66f4\u9ad8\u7ea7\u7684\u6570\u636e\u5904\u7406\u548c\u5206\u6790\u3002\u901a\u8fc7\u4ee5\u4e0a\u4ecb\u7ecd\u7684\u51e0\u79cd\u65b9\u6cd5\uff0c\u5e0c\u671b\u4f60\u80fd\u6839\u636e\u5b9e\u9645\u9700\u6c42\u9009\u62e9\u5408\u9002\u7684\u5de5\u5177\u548c\u65b9\u6cd5\uff0c\u6765\u5b9e\u73b0\u6570\u636e\u7684\u9ad8\u6548\u5904\u7406\u548c\u5206\u6790\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
 \u5982\u4f55\u5728Python\u4e2d\u4f7f\u7528\u5217\u540d\u6765\u8bbf\u95ee\u6570\u636e\u6846\u4e2d\u7684\u6570\u636e\uff1f<\/strong>
\u5728Python\u4e2d\uff0c\u4f7f\u7528Pandas\u5e93\u53ef\u4ee5\u8f7b\u677e\u5730\u901a\u8fc7\u5217\u540d\u8bbf\u95ee\u6570\u636e\u6846\u4e2d\u7684\u6570\u636e\u3002\u4f60\u53ef\u4ee5\u4f7f\u7528df['column_name']<\/code>\u7684\u65b9\u5f0f\u83b7\u53d6\u7279\u5b9a\u5217\u7684\u6570\u636e\uff0c\u5176\u4e2ddf<\/code>\u662f\u4f60\u7684\u6570\u636e\u6846\uff0ccolumn_name<\/code>\u662f\u4f60\u60f3\u8981\u8bbf\u95ee\u7684\u5217\u540d\u3002\u8fd9\u79cd\u65b9\u6cd5\u975e\u5e38\u76f4\u89c2\u4e14\u6613\u4e8e\u7406\u89e3\u3002<\/p>\n
\u5982\u679c\u5217\u540d\u5305\u542b\u7a7a\u683c\u6216\u7279\u6b8a\u5b57\u7b26\uff0c\u6211\u8be5\u5982\u4f55\u5904\u7406\uff1f<\/strong>
\u5f53\u5217\u540d\u5305\u542b\u7a7a\u683c\u6216\u7279\u6b8a\u5b57\u7b26\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u53cd\u5f15\u53f7\uff08\uff09\u6216\u901a\u8fc7<\/code>df.column_name\u7684\u65b9\u5f0f\u6765\u8bbf\u95ee\u3002\u4f8b\u5982\uff0c\u82e5\u5217\u540d\u4e3a\u201cColumn Name\u201d\uff0c\u53ef\u4ee5\u4f7f\u7528<\/code>df['Column Name']`\u6765\u5f15\u7528\u6b64\u5217\u3002\u786e\u4fdd\u5728\u5217\u540d\u4e2d\u4f7f\u7528\u6b63\u786e\u7684\u8bed\u6cd5\uff0c\u4ee5\u907f\u514d\u5f15\u53d1\u9519\u8bef\u3002<\/p>\n
\u5982\u4f55\u83b7\u53d6\u7279\u5b9a\u5217\u7684\u6570\u636e\u7c7b\u578b\uff1f<\/strong>
\u8981\u83b7\u53d6\u6570\u636e\u6846\u4e2d\u67d0\u4e00\u5217\u7684\u6570\u636e\u7c7b\u578b\uff0c\u53ef\u4ee5\u4f7f\u7528df['column_name'].dtype<\/code>\u3002\u8fd9\u5c06\u8fd4\u56de\u8be5\u5217\u7684\u6570\u636e\u7c7b\u578b\uff0c\u5982\u6574\u578b\u3001\u6d6e\u70b9\u578b\u6216\u5b57\u7b26\u4e32\u7b49\u3002\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\uff0c\u4f60\u53ef\u4ee5\u5feb\u901f\u4e86\u89e3\u6570\u636e\u7684\u7ed3\u6784\uff0c\u4ee5\u4fbf\u8fdb\u884c\u540e\u7eed\u7684\u6570\u636e\u5206\u6790\u548c\u5904\u7406\u3002<\/p>\n
\u5982\u4f55\u6539\u53d8\u67d0\u4e00\u5217\u7684\u6570\u636e\u7c7b\u578b\uff1f<\/strong>
\u5982\u679c\u9700\u8981\u66f4\u6539\u67d0\u4e00\u5217\u7684\u6570\u636e\u7c7b\u578b\uff0c\u53ef\u4ee5\u4f7f\u7528df['column_name'] = df['column_name'].astype(new_type)<\/code>\u7684\u65b9\u5f0f\uff0c\u5176\u4e2dnew_type<\/code>\u53ef\u4ee5\u662fint<\/code>\u3001float<\/code>\u6216str<\/code>\u7b49\u3002\u786e\u4fdd\u5728\u8fdb\u884c\u6570\u636e\u7c7b\u578b\u8f6c\u6362\u4e4b\u524d\u5bf9\u6570\u636e\u8fdb\u884c\u9002\u5f53\u7684\u68c0\u67e5\uff0c\u4ee5\u907f\u514d\u6f5c\u5728\u7684\u6570\u636e\u635f\u5931\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u5728Python\u4e2d\uff0c\u4f7f\u7528\u5217\u540d\u5f15\u7528\u6570\u636e\u7c7b\u578b\u7684\u5e38\u89c1\u65b9\u5f0f\u5305\u62ec\uff1a\u4f7f\u7528Pandas\u5e93\u3001\u4f7f\u7528CSV\u6a21\u5757\u3001\u4f7f\u7528SQLAlche […]","protected":false},"author":3,"featured_media":1073895,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1073889"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=1073889"}],"version-history":[{"count":"1","href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1073889\/revisions"}],"predecessor-version":[{"id":1073897,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1073889\/revisions\/1073897"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/1073895"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=1073889"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=1073889"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=1073889"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}