python中各种常见文件的读写操作与类型转换详细指南

file = open(file_path, mode='r', encoding=None)

#写入文件,当open(file_name,'w')时清除文件内容写入新内容，当open(file_name,'a')时直接在文件结尾加入新内容
file_name = 'text.txt'
try:
    with open(file_name,'w',encoding='utf-8') as file:
        file.write("你好！我是老叶爱吃鱼")
        file.write("\n你好呀，老叶，很高兴认识你")
except Exception as e:
    print(f'出错{e}')

#读取文件
try:
    with open(file_name,'r',encoding='utf-8') as file:
        print(file.read())
except Exception as e:
    print(f'出错时输出{e}')
#打印出：你好！我是老叶爱吃鱼     你好呀，老叶，很高兴认识你

# 打开文件
file = open('example.txt', 'r', encoding='utf-8')
# android读取第一行
line = file.readline()
while line:
    print(line.strip())  # strip() 方法用于去除行尾的换行符
    line = file.readline()
# 关闭文件
file.close()

# 打开文件
file = open('example.txt', 'r', encoding='utf-8')
# 读取所有行
lines = file.readlines()
for line in lines:
    print(line.strip())
# 关闭文件
file.close()

# 打开文件
file = open('example.txt', 'r', encoding='utf-8')
# 迭代文件对象
for line in file:
    print(line.strip())
# 关闭文件
file.close()

# 以二进制只读模式打开文件
with open('example.jpg', 'rb') as file:
    # 读取文件全部内容
    content = file.read()
    # 可以对二进制数据进行处理，如保存到另一个文件
    with open('copy.jpg', 'wb') as copy_file:
        copy_file.write(content)

# 逐行读取大文件
with open('large_file.twww.chinasem.cnxt', 'r', encoding='utf-8') as file:
    for line in file:
        # 处理每行内容
        print(line.strip())

# 分块读取大文件
chunk_size = 1024  # 每次读取 1024 字节
with open('large_file.txt', 'r', encoding='utf-8') as file:
    while True:
        chunk = file.read(chunk_size)
        if not chunk:
            break
        # 处理每个数据块
        print(chunk)

import xlrd
import xlwt
from datetime import date,datetime
 
 
# 打开文件
workbook = xlrd.open_workbook(r"D:\python_file\request_files\excelfile.xlsx", formatting_info=False)
# 获取所有的sheet
print("所有的工作表：",workbook.sheet_names())
sheet1 = workbook.sheet_names()[0]
 
# 根据sheet索引或者名称获取sheet内容
sheet1 = workbook.sheet_by_index(0)
sheet1 = workbook.sheet_by_name("Sheet1")
 
# 打印出所有合并的单元格
print(sheet1.merged_cells)
for (row,row_range,col,col_range) in sheet1.merged_cells:
    print(sheet1.cell_value(row,col))
 
# sheet1的名称、行数、列数
print("工作表名称：%s，行数：%d，列数：%d" % (sheet1.name, sheet1.nrows, sheet1.ncols))
 
# 获取整行和整列的值
row = sheet1.row_values(1)
col = sheet1.col_values(4)
print("第2行的值：%s" % row)
print("第5列的值：%s" % col)
 
# 获取单元格的内容
print("第一行第一列：%s" % sheet1.cell(0,0).value)
print("第一行第二列：%s" % sheet1.cell_value(0,1))
print("第一行第三列：%s" % sheet1.row(0)[2])
 
# 获取单元格内容的数据类型
# 类型 0 empty,1 string, 2 number, 3 date, 4 boolean, 5 error
print("第二行第三列的数据类型：%s" % sheet1.cell(3,2).ctype)
 
# 判断ctype类型是否等于data，如果等于，则用时间格式处理
if sheet1.cell(3,2).ctype == 3:
    data_value = xlrd.xldate_as_tuple(sheet1.cell_value(3, 2),workbook.datemode)
    print(data_value)
    print(date(*data_value[:3]))
    print(date(*data_value[:3]).strftime("%Y\%m\%d"))

style = xlwt.XFStyle()    # 初始化样式
font = xlwt.Font()    # 为样式创建字体
font.name = name    # 设置字体名字对应系统内字体
font.bold = bold    # 是否加粗
font.color_index = 5    # 设置字体颜色
font.height = height    # 设置字体大小
 
# 设置边框的大小
borders = xlwt.Borders()
borders.left = 6
borders.right = 6
borders.top = 6
borders.bottom = 6
 
style.font = font    # 为样式设置字体
style.borders = borders
 
return style

writeexcel = xlwt.Workbook()    # 创建工作表
sheet1 = writeexcel.add_sheet(u"Sheet1", cell_overwrite_ok = True)    # 创建sheet
 
row0 = ["编号", "姓名", "性别", "年龄", "生日", "学历"]
num = [1, 2, 3, 4, 5, 6, 7, 8]
column0 = ["a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8"]
education = ["小学", "初中", "高中", "大学"]
 
# 生成合并单元格
i,j = 1,0
while i < 2*len(education) and j < len(education):
    sheet1.write_merge(i, i+1, 5, 5, education[j], set_style("Arial", 200, True))
    i += 2
    j += 1
 
# 生成第一行
for i in range(0, 6):
    sheet1.write(0, i, row0[i])
 
# 生成前两列
for i in range(1, 9):
    sheet1.write(i, 0, i)
    sheet1.write(i, 1, "a1")
 
# 添加超链接
n = "HYperlINK"
sheet1.write_merge(9,9,0,5,xlwt.Formula(n + '("https://www.baidu.com")'))
 
# 保存文件
writeexcel.save("demo.xls")

# 读取 CSV 文件
def read_from_csv(file_path):
    try:
        with open(file_path, 'r', encoding='utf-8') as csvfile:
            reader = csv.reader(csvfile)
            print("读取到的 CSV 文件内容如下:")
            for row in reader:
                print(row)
    except FileNotFoundError:
        print(f"错误: 文件 {file_path} 未找到!")
    except Exception as e:
        print(f"读取文件时出错: {e}")
 

# 写入 CSV 文件
def write_to_csv(file_path, data):
    try:
        with open(file_path, 'w', newline='', encoding='utf-8') as csvfile:
            writer = csv.writer(csvfile)
            # 写入表头
            writer.writjserow(['Name', 'Age', 'City'])
            # 写入数据行
            for row in data:
                writer.writerow(row)
        print(f"数据已成功写入 {file_path}")
    except Exception as e:
        print(f"写入文件时出错: {e}")

import SQLite3
import pandas as pd
 
# 连接到SQLite数据库
conn = sqlite3.connect('example.db')
 
# 读取数据库表
query = "SELECT * FROM table_name"
data = pd.read_sql(query, conn)
print(data.head())
 
# 关闭连接
conn.close()

import pandas as pd
 
def xls_to_csv(xls_file_path, csv_file_path):
    try:
        df = pd.read_excel(xls_file_path)
        df.to_csv(csv_file_path, index=False)
        print(f"成功将 {xls_file_path} 转换为 {csv_file_path}")
    except Exception as e:
        print(f"转换过程中出现错误: {e}")
 
# 示例调用
xls_file = 'example.xls'
csv_file = 'example.csv'
xls_to_csv(xls_file, csv_file)

import pandas as pd
 
def csv_to_xls(csv_file_path, xls_file_pjavascriptath):
    try:
        df = pd.read_csv(csv_file_path)
        df.to_excel(xls_file_path, index=False)
        print(f"成功将 {csv_file_path} 转换为 {xls_file_path}")
    except Exception as e:
        print(f"转换过程中出现错误: {e}")
 
# 示例调用
csv_file = 'example.csv'
xls_file = 'example.xls'
csv_to_xls(csv_file, xls_file)

import pandas as pd
 
def txt_to_csv(txt_file_path, csv_file_path):
    try:
        # 假设 txt 文件以空格分隔，根据实际情况修改 sep 参数
        df = pd.read_csv(txt_file_path, sep=' ', header=None)
        df.to_csv(csv_file_path, index=False, header=False)
        print(f"成功将 {txt_file_path} 转换为 {csv_file_path}")
    except Exception as e:
        print(f"转换过程中出现错误: {e}")
 
# 示例调用
txt_file = 'example.txt'
csv_file = 'example.csv'
txt_to_csv(txt_file, csv_file)

import pandas as pd
 
def csv_to_txt(csv_file_path, txt_file_path):
    try:
        df = pd.read_csv(csv_file_path)
        df.to_csv(txt_file_path, sep=' ', index=False, header=False)
        print(f"成功将 {csv_file_path} 转换为 {txt_file_path}")
    except Exception as e:
        print(f"转换过程中出现错误: {e}")
 
# 示例调用
csv_file = 'example.csv'
txt_file = 'example.txt'
csv_to_txt(csv_file, txt_file)