pythoncsvwriter_python处理csv文件

原标题&＃xff1a;python 处理 csv 文件

csv 文件是一种逗号分隔的纯文本形式存储的表格数据&＃xff0c;Python内置了CSV模块&＃xff0c;可直接通过该模块实现csv文件的读写操作&＃xff0c;在web应用中导出数据是比较常见操作。

这篇文章介绍csv模块的基本用法

写操作

writer.writerow&＃xff0c; 将多列数据写入一行

importcsv

withopen( &＃39;some.csv&＃39;, &＃39;w&＃39;, newline&＃61; &＃39;&＃39;) asf:

writer &＃61; csv.writer(f)

writer.writerow([ "123", "234", "345"])

writer.writerow([ "abc", "efg", "hij"])

如果以文本文件的方式打开&＃xff0c;每行数据之间都是用逗号隔开的文本字符串

写入时&＃xff0c;必须指定 newline&＃61;’’&＃xff0c; 否则每插入一行就有一个空行

读操作withopen( &＃39;some.csv&＃39;, &＃39;r&＃39;, newline&＃61; "") asf:

reader &＃61; csv.reader(f)

forrow inreader:

print(row)

输出

[ &＃39;123&＃39;, &＃39;234&＃39;, &＃39;345&＃39;]

[ &＃39;abc&＃39;, &＃39;efg&＃39;, &＃39;hij&＃39;] DictWriter & DictReader

csv.DictWriter 对象引入了一个 fieldnames参数&＃xff0c; fieldnames是csv文件中的表头&＃xff0c;就是第一行中的数据

withopen( "person.csv", &＃39;w&＃39;, newline&＃61; &＃39;&＃39;) asf:

fieldnames &＃61; [ "name", "age", "sex"]

writer &＃61; csv.DictWriter(f, fieldnames&＃61;fieldnames)

writer.writeheader

writer.writerow({ "name": "zhangsan", "age": 10, "sex": "male"})

writer.writerow({ "name": "lis", "age": 20, "sex": "male"})

withopen( &＃39;person.csv&＃39;, &＃39;r&＃39;) asf:

reader &＃61; csv.DictReader(f)

forrow inreader:

print(row)

每行输出的是一个字典对象

OrderedDict([( &＃39;name&＃39;, &＃39;zhangsan&＃39;), ( &＃39;age&＃39;, &＃39;10&＃39;), ( &＃39;sex&＃39;, &＃39;male&＃39;)])

OrderedDict([( &＃39;name&＃39;, &＃39;lis&＃39;), ( &＃39;age&＃39;, &＃39;20&＃39;), ( &＃39;sex&＃39;, &＃39;male&＃39;)])

默认情况下导出的字符串全是数字时&＃xff0c;在excel中打开时会被自动转换成科学计数格式

importcsv

field_order &＃61; [ "会诊单号"]

withopen( "导出.csv", &＃39;w&＃39;, encoding&＃61; "utf8", newline&＃61; "") ascsvfile:

writer &＃61; csv.DictWriter(csvfile, field_order)

writer.writeheader

writer.writerow({ "会诊单号": "20210217162737860175"})

只需要在字符串后面加转义字符’t’即可变成字符串

importcsv

field_order &＃61; [ "会诊单号"]

withopen( "导出.csv", &＃39;w&＃39;, encoding&＃61; "utf8", newline&＃61; "") ascsvfile:

writer &＃61; csv.DictWriter(csvfile, field_order)

writer.writeheader

writer.writerow({ "会诊单号": "20210217162737860175"&＃43; &＃39;t&＃39;})

责任编辑&＃xff1a;