How do I fix the "wrong number of fields" with the missing commas in CSV file in Go?

Question

For my CSV files, every row has the same numbers of columns, except for the last row, which was only one column. So, when I read the file data with "foreach" for getting total number of rows, I get the error that it has the wrong number of fields. How do I fix this error without deleting the last row? The code and CSV file are shown below.

openfile, err := os.Open(filepath)
checkError("Error in reading the file\n", err)

fmt.Println("Already open filepath :", filepath)

//read the data of file
filedata, err := csv.NewReader(openfile).ReadAll()
checkError("Error in reading the file\n", err)

leg := len(filedata)

fmt.Println("total no of rows:", leg)

close := make([]string, leg)
date := make([]string, leg)
open := make([]string, leg)
high := make([]string, leg)
low := make([]string, leg)
adjustclose := make([]string, leg)
volume := make([]string, leg)

for e, value := range filedata {
    date[e] = value[0]
    open[e] = value[1]
    high[e] = value[2]
    low[e] = value[3]
    close[e] = value[4]
    adjustclose[e] = value[5]
    volume[e] = value[6]
}

2020-03-24,21,21,21,21,21,5
2020-04-06,20.8,20.8,20.8,20.8,20.8,19
2020-04-07,20.4,20.4,20.4,20.4,20.4,5
2020-04-09,20.4,20.4,20.4,20.4,20.4,10
292

See go doc encoding/csv.Reader.FieldsPerRecord. Allways, literally allways read the full documentation of any package you use. In the case you read the documentation but could make sense of it: Use -1. — Volker
– Volker, Commented Apr 21, 2020 at 6:09

user5728991 · Accepted Answer · 2020-04-21 06:10:45Z

37

Disable record length test in the CSV reader by setting FieldsPerRecord to a negative value.

csvr := csv.NewReader(openfile)
csvr.FieldsPerRecord = -1
filedata, err := csvr.ReadAll()

Test the record length in the application code:

for e, value := range filedata {
    if len(value) < 7 {
        continue  // skip short records
    }
    ...
}

Run it on the playground.

answered Apr 21, 2020 at 6:10

user5728991

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2 Comments

user12952781 Over a year ago

oh okay,thank you, it is work, but how do i store all the data into array ? i must create a slices or array right? but without the length of the filedata, how do i do it ?

user5728991 Over a year ago

@user12952781 Append values to the slices as you go. The example linked from the answer shows how to do this.

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