假定将行写入文件的循环无效

Question

I have a very large file that looks like this: [original file][1]

field number 7 (info) contains ~100 pairs of X=Y separated by ';'.

I first want to split all X=Y pairs.

Next I want to scan one pair at a time, and if X is one of 4 titles and Y is an int- I want to put them them in a dictionary.

After finishing going through the pairs I want to check if the dictionary contains all 4 of my titles, and if so, I want to calculate something and write it into a new file.

This is the part of my code which suppose to do that:

for row in reader:
    m = re.split(';',row[7])                                                # split the info field by ';'
    d = {}
    nl = []
    for c in m:                                                             # for each info field, split by '=', if it is one of the 4 fields wanted and the value is int- add it to a dict
        t = re.split('=',c)
        if (t[0]=='AC_MALE' or t[0]=='AC_FEMALE' or t[0]=='AN_MALE' or t[0]=='AN_FEMALE') and type(t[1])==int:
            d[t[0]] = t[1]
    if 'AC_MALE' in d and 'AC_FEMALE' in d and 'AN_MALE' in d and 'AN_FEMALE' in d:     # if the dict contain all 4 wanted fields- make a new line for the final file
        total_ac = int(d['AC_MALE'])+ int(d['AC_FEMALE'])
        total_an = int(d['AN_MALE'])+ int(d['AN_FEMALE'])
        ac_an = total_ac/total_an
        nl.extend([row[0],row[1],row[3],row[4],total_ac,total_an, ac_an])
        writer.writerow(nl)

The code is running with no errors but isnt writing anything to the file. Can someone figure out why?

Thanks!

Answer 1

type(t[1])==int is never true. t[1] is a string, always , because you just split that object from another string. It doesn't matter here if the string contains only digits and could be converted to a int .

Test if you can convert your string to an integer, and if that fails, just move on to the next. If it succeeds, add the value to your dictionary:

for c in m:
    t = re.split('=',c)
    if (t[0]=='AC_MALE' or t[0]=='AC_FEMALE' or t[0]=='AN_MALE' or t[0]=='AN_FEMALE'):
        try:
            d[t[0]] = int(t[1])
        except ValueError:
            # string could not be converted, so move on
            pass

Note that you don't need to use re.split() ; use the standard str.split() method instead. You don't need to test if all keys are present in your dictionary afterwards, just test if the dictionary contains 4 elements, so has a length of 4. You can also simplify the code to test the key name:

for row in reader:
    d = {}
    for key_value in row[7].split(','):
        key, value = key_value.split('=')
        if key in {'AC_MALE', 'AC_FEMALE', 'AN_MALE', 'AN_FEMALE'}:
            try:
                d[key] = int(value)
            except ValueError:
                pass
    if len(d) == 4:
        total_ac = d['AC_MALE'] + d['AC_FEMALE']
        total_an = d['AN_MALE'] + d['AN_FEMALE']
        ac_an = total_ac / total_an
        writer.writerow([
            row[0], row[1], row[3], row[4],
            total_ac, total_an, ac_an])