函数
>
读取和写入文件
> 示例：读取和写入 CSV 文件
示例：读取和写入 CSV 文件
有关使用此示例的信息，请参阅
要从帮助中复制数学示例
。
1.
使用
READCSV
读取 CSV 文件。
<region id="ID0EUJP1" top="96" left="24" width="152.376666666667" height="21.2" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="None">M1</id> <apply> <id>READCSV</id> <str xml:space="preserve">csv.txt</str> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
2.
显示所读取文件的内容。
<region id="ID0EELP1" top="192" left="24" width="90.0683333333333" height="53.012" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <eval xmlns="http://schemas.mathsoft.com/math50"> <id>M1</id> <result> <matrix rows="3" cols="3"> <real>1</real> <real>4</real> <real>7</real> <real>2</real> <real>5</real> <real>8</real> <real>3</real> <real>6</real> <real>9</real> </matrix> </result> </eval> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
3.
提取矩阵
M1
的三个列。
<region id="ID0EYMP1" top="312" left="24" width="57.8483333333333" height="29.414" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Variable">A</id> <apply> <matcol /> <id>M1</id> <real>2</real> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
<region id="ID0EGNP1" top="360" left="24" width="58.2316666666667" height="29.414" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Variable">B</id> <apply> <matcol /> <id>M1</id> <real>1</real> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
<region id="ID0EUNP1" top="408" left="24" width="58.265" height="29.414" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Variable">C</id> <apply> <matcol /> <id>M1</id> <real>0</real> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
4.
使用
augment
函数创建新矩阵
N
并显示其内容。
<region id="ID0E1PP1" top="504" left="24" width="127.523333333333" height="21.2" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Variable">N</id> <apply> <id>augment</id> <sequence> <id>A</id> <id>B</id> <id>C</id> </sequence> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
<region id="ID0EIQP1" top="552" left="24" width="82.215" height="53.012" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <eval xmlns="http://schemas.mathsoft.com/math50"> <id>N</id> <result> <matrix rows="3" cols="3"> <real>3</real> <real>6</real> <real>9</real> <real>2</real> <real>5</real> <real>8</real> <real>1</real> <real>4</real> <real>7</real> </matrix> </result> </eval> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
5.
使用
WRITECSV
将新矩阵写入到文件中。
<region id="ID0EHSP1" top="672" left="24" width="186.143333333333" height="21.2" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Function">T</id> <apply> <id label="Function">WRITECSV</id> <sequence> <str xml:space="preserve">csv_wr.txt</str> <id>N</id> </sequence> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
6.
读取新写入内容的 CSV 文件并显示其内容。
<region id="ID0EXTP1" top="768" left="24" width="171.636666666667" height="21.2" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <define xmlns="http://schemas.mathsoft.com/math50"> <id label="Variable">M2</id> <apply> <id>READCSV</id> <str xml:space="preserve">csv_wr.txt</str> </apply> </define> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
<region id="ID0EFUP1" top="816" left="24" width="90.0683333333333" height="53.012" xmlns="http://schemas.mathsoft.com/worksheet50"> <math> <eval xmlns="http://schemas.mathsoft.com/math50"> <id>M2</id> <result> <matrix rows="3" cols="3"> <real>3</real> <real>6</real> <real>9</real> <real>2</real> <real>5</real> <real>8</real> <real>1</real> <real>4</real> <real>7</real> </matrix> </result> </eval> <resultFormat> <matrix size="12,12" offset="0,0" /> </resultFormat> </math> </region>
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