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How to read csv file in golang

Dec 31, 2019 am 10:18 AM
golang

How to read csv file in golang

go语言读取CSV的方法:

package main
 
import (
    "encoding/csv"
    "fmt"
    "io"
    "log"
    "os"
)
 
func main() {
    //准备读取文件
    fileName := "D:\\gotest\\src\\source\\test.csv"
    fs, err := os.Open(fileName)
    if err != nil {
        log.Fatalf("can not open the file, err is %+v", err)
    }
    defer fs.Close()
 
    r := csv.NewReader(fs)
    //针对大文件,一行一行的读取文件
    for {
        row, err := r.Read()
        if err != nil && err != io.EOF {
            log.Fatalf("can not read, err is %+v", err)
        }
        if err == io.EOF {
            break
        }
        fmt.Println(row)
    }
 
    //针对小文件,也可以一次性读取所有的文件
    //注意,r要重新赋值,因为readall是读取剩下的
    fs1, _ := os.Open(fileName)
    r1 := csv.NewReader(fs1)
    content, err := r1.ReadAll()
    if err != nil {
        log.Fatalf("can not readall, err is %+v", err)
    }
    for _, row := range content {
        fmt.Println(row)
    }
 
}
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os包是系统标准库里面有操作系统相关的函数和变量,打开一个文件可以使用os.open。

strings.Reader类型的值(以下简称Reader值)可以让我们很方便地读取一个字符串中的内容。在读取的过程中,Reader值会保存已读取的字节的计数(以下简称已读计数)。

已读计数也代表着下一次读取的起始索引位置。Reader值正是依靠这样一个计数,以及针对字符串值的切片表达式,从而实现快速读取。

更多golang知识请关注golang教程栏目。

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