[hail] if an MT is string-column-keyed, use said strings in show

[danking]

Previously the below would display 0.GT | 1.GT (simply the index in the entries array).

In [2]: import hail as hl  
   ...: mt = hl.balding_nichols_model(3, 100, 100) 
   ...: mt = mt.key_cols_by(sample_id = 'sample-' + hl.str(mt.sample_idx)) 
   ...: mt.show(n_rows=10, n_cols=10)                                                                                                                                                                               
2019-06-19 16:20:33 Hail: INFO: balding_nichols_model: generating genotypes for 3 populations, 100 samples, and 100 variants...
+---------------+------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
| locus         | alleles    | sample-0.GT | sample-1.GT | sample-2.GT | sample-3.GT | sample-4.GT | sample-5.GT | sample-6.GT | sample-7.GT | sample-8.GT | sample-9.GT |
+---------------+------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
| locus<GRCh37> | array<str> | call        | call        | call        | call        | call        | call        | call        | call        | call        | call        |
+---------------+------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
| 1:1           | ["A","C"]  | 0/0         | 0/0         | 0/1         | 1/1         | 0/1         | 0/0         | 0/1         | 0/1         | 0/1         | 0/1         |
| 1:2           | ["A","C"]  | 1/1         | 0/1         | 0/0         | 0/1         | 1/1         | 1/1         | 0/1         | 1/1         | 0/0         | 1/1         |
| 1:3           | ["A","C"]  | 1/1         | 0/1         | 0/0         | 1/1         | 0/0         | 1/1         | 1/1         | 0/1         | 0/0         | 1/1         |
| 1:4           | ["A","C"]  | 0/0         | 0/1         | 0/0         | 1/1         | 0/1         | 0/0         | 0/1         | 0/0         | 0/0         | 0/1         |
| 1:5           | ["A","C"]  | 0/1         | 0/0         | 0/0         | 0/0         | 0/1         | 0/0         | 0/1         | 0/1         | 0/0         | 1/1         |
| 1:6           | ["A","C"]  | 0/0         | 1/1         | 1/1         | 0/1         | 0/1         | 1/1         | 0/1         | 0/1         | 1/1         | 1/1         |
| 1:7           | ["A","C"]  | 0/0         | 0/1         | 1/1         | 0/1         | 0/1         | 0/1         | 0/0         | 0/1         | 0/0         | 0/1         |
| 1:8           | ["A","C"]  | 0/1         | 0/1         | 1/1         | 1/1         | 0/1         | 0/1         | 1/1         | 1/1         | 0/1         | 0/1         |
| 1:9           | ["A","C"]  | 0/0         | 0/1         | 1/1         | 1/1         | 1/1         | 0/1         | 1/1         | 1/1         | 1/1         | 1/1         |
| 1:10          | ["A","C"]  | 0/1         | 0/1         | 0/1         | 0/0         | 0/1         | 0/0         | 0/1         | 0/1         | 0/0         | 0/1         |
+---------------+------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
showing top 10 rows
showing the first 10 of 100 columns

In [3]:  

[patrick-schultz]

awesome