Minor fix in `iter_files` for hidden files

Fix #6090

Comments:
_The documentation is not available anymore as the PR was closed or merged._

<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007873 / 0.011353 (-0.003480) | 0.004585 / 0.011008 (-0.006423) | 0.101622 / 0.038508 (0.063114) | 0.092459 / 0.023109 (0.069350) | 0.365157 / 0.275898 (0.089259) | 0.405943 / 0.323480 (0.082463) | 0.006229 / 0.007986 (-0.001756) | 0.003811 / 0.004328 (-0.000518) | 0.073831 / 0.004250 (0.069580) | 0.065097 / 0.037052 (0.028045) | 0.378912 / 0.258489 (0.120423) | 0.422174 / 0.293841 (0.128333) | 0.036244 / 0.128546 (-0.092302) | 0.009677 / 0.075646 (-0.065970) | 0.345164 / 0.419271 (-0.074107) | 0.061632 / 0.043533 (0.018099) | 0.370350 / 0.255139 (0.115211) | 0.418245 / 0.283200 (0.135046) | 0.027272 / 0.141683 (-0.114411) | 1.774047 / 1.452155 (0.321892) | 1.880278 / 1.492716 (0.387562) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.217238 / 0.018006 (0.199231) | 0.489560 / 0.000490 (0.489071) | 0.004013 / 0.000200 (0.003813) | 0.000092 / 0.000054 (0.000038) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.034139 / 0.037411 (-0.003272) | 0.103831 / 0.014526 (0.089305) | 0.114353 / 0.176557 (-0.062204) | 0.182034 / 0.737135 (-0.555102) | 0.116171 / 0.296338 (-0.180168) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.448658 / 0.215209 (0.233449) | 4.520849 / 2.077655 (2.443195) | 2.216121 / 1.504120 (0.712001) | 2.034596 / 1.541195 (0.493402) | 2.193216 / 1.468490 (0.724725) | 0.568166 / 4.584777 (-4.016611) | 4.133587 / 3.745712 (0.387875) | 4.641117 / 5.269862 (-0.628744) | 2.772913 / 4.565676 (-1.792764) | 0.067664 / 0.424275 (-0.356611) | 0.008719 / 0.007607 (0.001112) | 0.547723 / 0.226044 (0.321678) | 5.438325 / 2.268929 (3.169397) | 2.877667 / 55.444624 (-52.566958) | 2.477503 / 6.876477 (-4.398974) | 2.688209 / 2.142072 (0.546136) | 0.692593 / 4.805227 (-4.112634) | 0.154549 / 6.500664 (-6.346115) | 0.073286 / 0.075469 (-0.002183) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.610927 / 1.841788 (-0.230861) | 23.413345 / 8.074308 (15.339037) | 16.851819 / 10.191392 (6.660427) | 0.170076 / 0.680424 (-0.510348) | 0.021428 / 0.534201 (-0.512773) | 0.468184 / 0.579283 (-0.111099) | 0.491820 / 0.434364 (0.057456) | 0.553453 / 0.540337 (0.013115) | 0.762303 / 1.386936 (-0.624633) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.008033 / 0.011353 (-0.003320) | 0.004638 / 0.011008 (-0.006370) | 0.077044 / 0.038508 (0.038536) | 0.096529 / 0.023109 (0.073420) | 0.428735 / 0.275898 (0.152837) | 0.477303 / 0.323480 (0.153823) | 0.006040 / 0.007986 (-0.001946) | 0.003808 / 0.004328 (-0.000521) | 0.076042 / 0.004250 (0.071791) | 0.066123 / 0.037052 (0.029071) | 0.445482 / 0.258489 (0.186993) | 0.481350 / 0.293841 (0.187509) | 0.036951 / 0.128546 (-0.091595) | 0.009944 / 0.075646 (-0.065703) | 0.082731 / 0.419271 (-0.336541) | 0.057490 / 0.043533 (0.013958) | 0.432668 / 0.255139 (0.177529) | 0.461146 / 0.283200 (0.177947) | 0.027330 / 0.141683 (-0.114353) | 1.784195 / 1.452155 (0.332040) | 1.834776 / 1.492716 (0.342059) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.254104 / 0.018006 (0.236097) | 0.475810 / 0.000490 (0.475321) | 0.000459 / 0.000200 (0.000259) | 0.000069 / 0.000054 (0.000014) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.037058 / 0.037411 (-0.000353) | 0.114962 / 0.014526 (0.100436) | 0.123725 / 0.176557 (-0.052832) | 0.188885 / 0.737135 (-0.548251) | 0.125668 / 0.296338 (-0.170670) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.492627 / 0.215209 (0.277418) | 4.900625 / 2.077655 (2.822970) | 2.546349 / 1.504120 (1.042229) | 2.360350 / 1.541195 (0.819155) | 2.477975 / 1.468490 (1.009485) | 0.574042 / 4.584777 (-4.010735) | 4.408414 / 3.745712 (0.662702) | 3.836640 / 5.269862 (-1.433222) | 2.438450 / 4.565676 (-2.127227) | 0.067706 / 0.424275 (-0.356569) | 0.009165 / 0.007607 (0.001558) | 0.580313 / 0.226044 (0.354269) | 5.798211 / 2.268929 (3.529283) | 3.098480 / 55.444624 (-52.346145) | 2.740180 / 6.876477 (-4.136296) | 2.984548 / 2.142072 (0.842476) | 0.702550 / 4.805227 (-4.102677) | 0.158248 / 6.500664 (-6.342416) | 0.073999 / 0.075469 (-0.001470) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.636034 / 1.841788 (-0.205754) | 24.068000 / 8.074308 (15.993692) | 17.123987 / 10.191392 (6.932595) | 0.210101 / 0.680424 (-0.470323) | 0.022555 / 0.534201 (-0.511646) | 0.509354 / 0.579283 (-0.069929) | 0.540739 / 0.434364 (0.106375) | 0.546048 / 0.540337 (0.005711) | 0.719155 / 1.386936 (-0.667781) |

</details>
</details>

![](https://cml.dev/watermark.png#40530382ba98f54445de8820943b1236d4a4704f "CML watermark")


<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007342 / 0.011353 (-0.004010) | 0.004579 / 0.011008 (-0.006429) | 0.087050 / 0.038508 (0.048542) | 0.089001 / 0.023109 (0.065892) | 0.307319 / 0.275898 (0.031421) | 0.377573 / 0.323480 (0.054093) | 0.006472 / 0.007986 (-0.001514) | 0.004287 / 0.004328 (-0.000041) | 0.067226 / 0.004250 (0.062976) | 0.063147 / 0.037052 (0.026094) | 0.314541 / 0.258489 (0.056052) | 0.369919 / 0.293841 (0.076078) | 0.031283 / 0.128546 (-0.097263) | 0.009175 / 0.075646 (-0.066471) | 0.289211 / 0.419271 (-0.130061) | 0.053444 / 0.043533 (0.009911) | 0.307308 / 0.255139 (0.052169) | 0.346221 / 0.283200 (0.063021) | 0.027948 / 0.141683 (-0.113735) | 1.475177 / 1.452155 (0.023022) | 1.575971 / 1.492716 (0.083255) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.291092 / 0.018006 (0.273086) | 0.696951 / 0.000490 (0.696461) | 0.005211 / 0.000200 (0.005011) | 0.000094 / 0.000054 (0.000040) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.031787 / 0.037411 (-0.005625) | 0.084382 / 0.014526 (0.069857) | 0.106474 / 0.176557 (-0.070083) | 0.161472 / 0.737135 (-0.575663) | 0.108650 / 0.296338 (-0.187688) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.379656 / 0.215209 (0.164447) | 3.784072 / 2.077655 (1.706417) | 1.826580 / 1.504120 (0.322460) | 1.654916 / 1.541195 (0.113721) | 1.730698 / 1.468490 (0.262208) | 0.478003 / 4.584777 (-4.106774) | 3.564920 / 3.745712 (-0.180792) | 5.824873 / 5.269862 (0.555012) | 3.454563 / 4.565676 (-1.111113) | 0.056646 / 0.424275 (-0.367629) | 0.007410 / 0.007607 (-0.000197) | 0.461781 / 0.226044 (0.235737) | 4.600928 / 2.268929 (2.331999) | 2.351887 / 55.444624 (-53.092738) | 1.986470 / 6.876477 (-4.890007) | 2.311623 / 2.142072 (0.169551) | 0.571247 / 4.805227 (-4.233980) | 0.132191 / 6.500664 (-6.368473) | 0.059943 / 0.075469 (-0.015526) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.253142 / 1.841788 (-0.588646) | 21.294983 / 8.074308 (13.220675) | 14.522429 / 10.191392 (4.331037) | 0.166663 / 0.680424 (-0.513761) | 0.019694 / 0.534201 (-0.514507) | 0.395908 / 0.579283 (-0.183375) | 0.413283 / 0.434364 (-0.021081) | 0.457739 / 0.540337 (-0.082599) | 0.664361 / 1.386936 (-0.722575) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007228 / 0.011353 (-0.004124) | 0.004941 / 0.011008 (-0.006067) | 0.065381 / 0.038508 (0.026873) | 0.090790 / 0.023109 (0.067681) | 0.391315 / 0.275898 (0.115417) | 0.416518 / 0.323480 (0.093038) | 0.007015 / 0.007986 (-0.000970) | 0.004417 / 0.004328 (0.000089) | 0.067235 / 0.004250 (0.062985) | 0.068092 / 0.037052 (0.031039) | 0.403031 / 0.258489 (0.144542) | 0.434013 / 0.293841 (0.140172) | 0.032004 / 0.128546 (-0.096542) | 0.009242 / 0.075646 (-0.066404) | 0.071222 / 0.419271 (-0.348050) | 0.054207 / 0.043533 (0.010674) | 0.386198 / 0.255139 (0.131059) | 0.404350 / 0.283200 (0.121150) | 0.036284 / 0.141683 (-0.105399) | 1.488814 / 1.452155 (0.036660) | 1.587785 / 1.492716 (0.095069) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.313760 / 0.018006 (0.295754) | 0.747778 / 0.000490 (0.747289) | 0.003307 / 0.000200 (0.003107) | 0.000113 / 0.000054 (0.000058) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.034321 / 0.037411 (-0.003090) | 0.088266 / 0.014526 (0.073740) | 0.112874 / 0.176557 (-0.063682) | 0.171554 / 0.737135 (-0.565581) | 0.111356 / 0.296338 (-0.184982) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.422624 / 0.215209 (0.207415) | 4.212079 / 2.077655 (2.134425) | 2.242742 / 1.504120 (0.738622) | 2.072555 / 1.541195 (0.531360) | 2.192648 / 1.468490 (0.724158) | 0.488214 / 4.584777 (-4.096563) | 3.597013 / 3.745712 (-0.148699) | 3.477556 / 5.269862 (-1.792305) | 2.184340 / 4.565676 (-2.381337) | 0.057170 / 0.424275 (-0.367105) | 0.007772 / 0.007607 (0.000165) | 0.499455 / 0.226044 (0.273411) | 4.988953 / 2.268929 (2.720024) | 2.797894 / 55.444624 (-52.646731) | 2.402215 / 6.876477 (-4.474262) | 2.725069 / 2.142072 (0.582997) | 0.596213 / 4.805227 (-4.209014) | 0.136564 / 6.500664 (-6.364100) | 0.061799 / 0.075469 (-0.013670) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.360739 / 1.841788 (-0.481049) | 21.846457 / 8.074308 (13.772149) | 14.568842 / 10.191392 (4.377450) | 0.168980 / 0.680424 (-0.511444) | 0.018795 / 0.534201 (-0.515406) | 0.396173 / 0.579283 (-0.183110) | 0.418651 / 0.434364 (-0.015713) | 0.480042 / 0.540337 (-0.060295) | 0.650803 / 1.386936 (-0.736133) |

</details>
</details>

![](https://cml.dev/watermark.png#b7d460304487d4daab0a64ca0ca707e896367ca1 "CML watermark")