Python – Use multiple str.startswith() in a for loop get their specific values

Question

The below function parses multiple csv files in a directory and takes out values using str.startwith().

It works find using ‘firstline.startswith(‘TrakPro’)‘ and ‘txt.startswith('Serial')‘. However, when I add a third str.startwith() i.e. txt2.startswith(‘Test’), nothing prints out, no error, appears to ignore it. What do I need to change? Basically I want to add multiple str.startwith() in the for loop pulling out various key words after the ‘:".

def get_csv_file_list(root):
    for r, d, f in os.walk(root):
        for file in f:

            if file.endswith('.csv'):
                path = os.path.join(r, file)
                dir_name = path.split(os.path.sep)[-2]
                file_name = os.path.basename(file)

                try:
                    with open(path) as k:
                        firstline = k.readline()

                        if firstline.startswith('TrakPro'):
                            file_list.append(path)
                            file_list.append(dir_name)
                            file_list.append(file_name)

                            txt = 'Serial Number:'
                            if txt.startswith('Serial'):
                                for row in list(k)[3:4]:
                                    file_list.append(row[15:26])

                            txt2 = 'Test Name:'
                            if txt2.startswith('Test'):
                                for rows in list(k)[4:5]:
                                    print(rows)
                                    file_list.append(row[11:])

The csv looks like this:

TrakPro Version 5.2.0.0 ASCII Data File
Instrument Name:,SidePak
Model Number:,TK0W02
Serial Number:,120k2136005
Test Name:,13270
Start Date:,04/17/2021
Start Time:,01:53:29
Duration (dd:hh:mm:ss):,00:07:13:00
Log Interval (mm:ss):,01:00
Number of points:,433
Description:,

So far I have tried the above code, I expected to print out values in the ‘Test Name’ line of the csv sample. The function does not print out anything, no error.

Tks

Asked By: ksu1980

||

Source

Answer 1

To print only the value of the line that starts with Test Name: you can use following code:

with open("your_file.csv", "r") as f_in:
    for line in map(str.strip, f_in):
        if line.startswith("Test Name:"):
            _, value = line.split(",", maxsplit=1)
            print(value)

Prints:

Answered By: Andrej Kesely

Answer 2

As I said in my comment, you are consuming k as you go.

To see what is going on, run the following:

file_name = "./abc.csv"
file_list=[]
with open(file_name) as k:
    firstline = k.readline() # Consume first line
    if firstline.startswith('TrakPro'):
        print("First line:n", firstline)
        file_list.append(file_name)
        txt = list(k) # here k is the file contents minus the first line
        print("Contents of listn", txt)
        if str(txt[2]).startswith('Serial'):
            file_list.append(str(txt[2])[15:26])
        if str(txt[3]).startswith('Test'):
            file_list.append(str(txt[3].strip())[11:])
print("nResult:n",file_list)

Where the contents of abc.csv are:

TrakPro Version 5.2.0.0 ASCII Data File
Instrument Name:,SidePak
Model Number:,TK0W02
Serial Number:,120k2136005
Test Name:,13270
Start Date:,04/17/2021
Start Time:,01:53:29
Duration (dd:hh:mm:ss):,00:07:13:00
Log Interval (mm:ss):,01:00
Number of points:,433
Description:,

The result should be:

First line:
 TrakPro Version 5.2.0.0 ASCII Data File

Contents of list
 ['Instrument Name:,SidePakn', 'Model Number:,TK0W02n', 'Serial Number:,120k2136005n', 'Test Name:,13270n', 'Start Date:,04/17/2021n', 'Start Time:,01:53:29n', 'Duration (dd:hh:mm:ss):,00:07:13:00n', 'Log Interval (mm:ss):,01:00n', 'Number of points:,433n', 'Description:,n']

Result:
 ['./abc.csv', '120k2136005', '13270']

Answered By: Rolf of Saxony

Python – Use multiple str.startswith() in a for loop get their specific values

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