Python best way to check if key in dict and use value

Question

I have a dictionary like:

{
  'cashflowStatements': [
    {
      'endDate': '2019',
      'totalCashFromOperatingActivities': -40743000,
      'capitalExpenditures': -46141000
    },
    {
      'totalCashflowsFromInvestingActivities': 148919000,
      'endDate': '2018',
      'capitalExpenditures': -53753000
    },
    {
      'totalCashflowsFromInvestingActivities': -45493000,
      'endDate': '2017',
    },
    {
      'totalCashflowsFromInvestingActivities': -19651000,
      'endDate': '2016',
      'capitalExpenditures': -26266000
    }
  ]
}

I want to add the values to a variable, if they are in the dictionary.

Currently I have this solution for that:

       for year in dict['cashflowStatements']:
            freeCashflow = 0
            if 'totalCashFromOperatingActivities' in year:
                freeCashflow += year['totalCashFromOperatingActivities']
            if 'capitalExpenditures' in year:
                freeCashflow += year['capitalExpenditures']

Is there a better way to do this, maybe with less lines of code?

Yep, haven't known this yet. Thank you! – michaelgr22 Aug 09 '20 at 08:32 — michaelgr22, Aug 09 '20 at 08:32

score 1 · Accepted Answer · answered Aug 09 '20 at 08:32

1

Maybe something like this:

for year in dict['cashflowStatements']:
    freeCashflow = year.get('totalCashFromOperatingActivities', 0) + year.get('capitalExpenditures', 0)

answered Aug 09 '20 at 08:32

rajkris

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If we want `freeCashflow` to be intialized with the data present in the last dict of list ONLY, then why to iterate the entire list ? We can simply get last dict from list and use that. – Tabaene Haque Aug 09 '20 at 08:41
Maybe the code is not complete. More logic to be added in the loop. It depends on the questioners requirement – rajkris Aug 09 '20 at 08:49

Tabaene Haque · Answer 2 · 2020-08-09T08:48:43.570

Pythonic would be to use list comprehension like this -

d = {
  'cashflowStatements': [
    {
      'endDate': '2019',
      'totalCashFromOperatingActivities': -40743000,
      'capitalExpenditures': -46141000
    },
    {
      'totalCashflowsFromInvestingActivities': 148919000,
      'endDate': '2018',
      'capitalExpenditures': -53753000
    },
    {
      'totalCashflowsFromInvestingActivities': -45493000,
      'endDate': '2017',
    },
    {
      'totalCashflowsFromInvestingActivities': -19651000,
      'endDate': '2016',
      'capitalExpenditures': -26266000
    }
  ]
}

print(sum([year.get('totalCashFromOperatingActivities', 0) + year.get('capitalExpenditures', 0) for year in d['cashflowStatements']]))

Output: -166903000

Also looking at the question it seems like we want freeCashflow to be initialized with the sum of data present in last dict of list ONLY, then use below code.

print(d["cashflowStatements"][-1].get('totalCashFromOperatingActivities', 0) + d["cashflowStatements"][-1].get('capitalExpenditures', 0))

Output: -26266000

'freeCashflow' is reinitialized in each loop. So I think this won't behave the same way as in question — rajkris, Aug 09 '20 at 08:34

Python best way to check if key in dict and use value

2 Answers2