How to generate properties of instances of classes in batches?

Question

I have a class named MyClass. I want to generate the attributes k_10sec to k_1d of the instance in batches when generating instances of the class.

How do I modify the code?

bars = ['10sec', '1min', '5min', '30min', '1d']


class MyClass:
    def __init__(self):
        for bar in bars:
            if bar.endswith('sec'):
                duration_seconds = int(bar[:-3])
            elif bar.endswith('min'):
                duration_seconds = int(bar[:-3] * 60)
            elif bar.endswith('d'):
                duration_seconds = int(bar[:-1] * 60 * 60 * 24)
            self.globals()[f'k_{bar}'] = duration_seconds


s1 = MyClass()
for bar in bars:
    print(s1.[f'k_{bar}'])

My expected result:

Finally, I combined the two methods and used them together.

import re


def parse_time(bar='', secs=0):
    if bar != '':
        bar = re.split('(\d+)', bar)
        if bar[2] in ('sec', 's'):
            secs = int(bar[1])
        elif bar[2] == 'min':
            secs = int(bar[1]) * 60
        elif bar[2] in ('hour', 'h'):
            secs = int(bar[1]) * 60 * 60
        elif bar[2] in ('d', 'day', 'D'):
            secs = int(bar[1]) * 60 * 60 * 24
        else:
            pass
        return secs
    elif secs != 0:
        if secs % (60 * 60 * 24) == 0:
            bar = str(secs // (60 * 60 * 24)) + 'day'
        elif secs % (60 * 60) == 0:
            bar = str(secs // (60 * 60)) + 'hour'
        elif secs % 60 == 0:
            bar = str(secs // 60) + 'min'
        else:
            bar = str(secs) + 'sec'
        return bar
    else:
        pass


class MyClass:
    def __init__(self, bars):
        self.d = {f'k_{bar}': parse_time(bar=bar) for bar in bars}


if __name__ == '__main__':
    bars = ['10sec', '1min', '5min', '30min', '1d']
    s1 = MyClass(bars)
    pass

`self.a = list(range(100))`. Why do you need 100 separate attributes? — chepner, Jun 22 '21 at 13:35
Does this answer your question? [How do I create variable variables?](https://stackoverflow.com/questions/1373164/how-do-i-create-variable-variables) — quamrana, Jun 22 '21 at 13:38
Use a dictionary to store the values using the "variable name" as the key. — Eric McLachlan, Jun 22 '21 at 13:40
@quamrana I have implemented the use of variable variables, but I have not found a way to use variable variables in the class. — jaried, Jun 22 '21 at 14:10

chepner · Accepted Answer · 2021-06-22T14:15:09.853

You don't need globals; that's a function in the built-in scope for providing a dict interface to the global variables. Just use a regular dict

class MyClass:
    def __init__(self, bars):
        self.d = {}
        for bar in bars:
            if bar.endswith('sec'):
                duration_seconds = int(bar[:-3])
            elif bar.endswith('min'):
                duration_seconds = int(bar[:-3]) * 60
            elif bar.endswith('d'):
                duration_seconds = int(bar[:-1]) * 60 * 60 * 24
            self.d[f'k_{bar}'] = duration_seconds

s1 = MyClass(['10sec', '1min', '5min', '30min', '1d'])
for bar in s1.d:
    print(s1.d[bar])

I would move the logic of converting a time string to a number of seconds to a separate function, though:

def parse_time(s):
    if s.endswith('sec'):
        return int(s[:-3])
    elif s.endswith('min'):
        return int(s[:-3]) * 60
    elif s.endswith('d'):
        return int(s[:-1]) * 60 * 60 * 24


class MyClass:
    def __init__(self, bars):
        self.d = {f'k_{bar}': parse_time(bar) for bar in bars}

score 1 · Answer 2 · answered Jun 22 '21 at 14:27

I wrote a very simple solution, hope that was you intention

import re

bars = ['10sec', '1min', '5min', '30min', '1d']

class MyClass:
    def duration_seconds(self, bar):
        bar = re.split('(\d+)', bar)
        if bar[2] == 'sec':
            secs = int(bar[1])
        elif bar[2] == 'min':
            secs = int(bar[1]) * 60
        elif bar[2] == 'd':
            secs = int(bar[1]) * 60 * 60 * 24
        return secs


s1 = MyClass()
for bar in bars:
    print(s1.duration_seconds('k_{0}'.format(bar)))

Finally, I combined the two methods and used them together. – jaried Jun 23 '21 at 05:01 — jaried, Jun 23 '21 at 05:01

How to generate properties of instances of classes in batches?

2 Answers2