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DOC: Update to docstring of pd.DataFrame(dtype) #14868

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DOC: Update to docstring of pd.DataFrame(dtype) #14868

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DOC: Update to docstring of pd.DataFrame(dtype)
patniharshit Dec 12, 2016
65e7620
DOC: remove Exceptional Behaviour
patniharshit Dec 13, 2016
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15 changes: 15 additions & 0 deletions pandas/core/frame.py
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Original file line number Diff line number Diff line change
Expand Up @@ -231,6 +231,21 @@ class DataFrame(NDFrame):
>>> df3 = DataFrame(np.random.randn(10, 5),
... columns=['a', 'b', 'c', 'd', 'e'])

Leaving dtype=None in constructor will infer a wider type than necessary
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can you show an a typical example of passing a dtype, with a single type, then multiple types, then this example.

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What do you mean by an example passing multiple types? Is that possible to pass in multiple types?

>>> df_cols = {'year':np.int32, 'month':np.int8}
>>> df = pd.DataFrame(columns=df_cols.keys(), dtype=None, index=range(10), data=-1)
>>> df.dtypes
month int64
year int64

A list/dict/Series/array-like is not allowed. Also behaves differently to read_csv(dtype)
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not sure what you are trying to show here, this is just confusing (after line 241)

>>> df = pd.DataFrame(columns=df_cols.keys(), dtype=np.int32, index=range(10), data=-1)

df.dtypes shows they're all np.int32
Fix up dtypes after declaration
>>> for col,coltype in df_cols.items():
... df[col] = df[col].astype(coltype)

See also
--------
DataFrame.from_records : constructor from tuples, also record arrays
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