{"kind":"task","effective_mode":"full","benchmark":{"kind":"benchmark","effective_mode":"full","slug":"ds-1000","formal_name":"DS-1000","introduction":"DS-1000 builds 1,000 data-science problems from real StackOverflow questions across seven libraries including NumPy, Pandas and Matplotlib. The problems are perturbed so that recalling the original answer does not solve them.","introduction_ja":"","introduction_en":"","category":"Category not supplied","task_count":null,"acquisition_status":"Acquisition status not supplied","official_url":"https://ds1000-code-gen.github.io/","indexing_mode":"noindex","profile":{"resources":[],"task_format":"","scoring":"","metric":"","size":"","answer_access":"","license":"","citation":"","maintainer":"","released":"","why_hard":"","related":[]}},"task_id":"15892217-bc19-5361-9761-ec3d10f2fc90","task_key":"default--test--91","task_revision_id":"2","upstream_id":"91","short_description":"I have multi-index df as follows","config":"default","split":"test","body":"{\"prompt\":\"Problem:\\nI have multi-index df as follows\\n\\n\\n                x  y\\nid  date            \\nabc 3/1/1994  100  7\\n    9/1/1994   90  8\\n    3/1/1995   80  9\\nWhere dates are stored as str.\\n\\n\\nI want to parse date index. The following statement\\n\\n\\ndf.index.levels[1] = pd.to_datetime(df.index.levels[1])\\nreturns error:\\n\\n\\nTypeError: 'FrozenList' does not support mutable operations.\\n\\n\\nA:\\n<code>\\nimport pandas as pd\\n\\n\\nindex = pd.MultiIndex.from_tuples([('abc', '3/1/1994'), ('abc', '9/1/1994'), ('abc', '3/1/1995')],\\n                                 names=('id', 'date'))\\ndf = pd.DataFrame({'x': [100, 90, 80], 'y':[7, 8, 9]}, index=index)\\n</code>\\ndf = ... # put solution in this variable\\nBEGIN SOLUTION\\n<code>\\n\"}","display_format":"code","language":"","answer_status":"published","assets":[],"source_url":"https://ds1000-code-gen.github.io/","history":"initial import","indexing_mode":"noindex","subproblems":[],"grids":[]}