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Dictionaries · Creating Dictionaries · Practice Question

Unique Keys

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Question

Create a dictionary with:

  • 10 unique long keys
  • Keys randomly selected from the integers between 0 and 99
  • 10 random float values between 0 and 100

Solution

d:(-10?100)!10?100.0

Example result:

21| 42.37631
87| 91.84272
3 | 17.46392
64| 55.1208
9 | 6.945217
38| 73.50618
72| 28.39471
14| 81.6274
56| 49.01822
95| 12.77483

Explanation

-10?100 rolls 10 unique longs without replacement from 0–99 (the keys); 10?100.0 rolls 10 floats with replacement (the values). ! pairs them into the dictionary.

The negative left argument is what guarantees unique keys. Note that without-replacement sampling requires the domain to be at least as large as the count requested — -10?8 fails with 'length since only 8 distinct values exist for 10 requested keys.