Dask DataFrame¶A Dask DataFrame is a large parallel DataFrame composed of many smaller pandas DataFrames, split along the index. These pandas DataFrames may live on disk for larger-than-memory computing on a single machine, or on many different machines in a cluster. One Dask DataFrame operation triggers many operations on the constituent pandas DataFrames. Show
Design¶Dask DataFrames coordinate many pandas DataFrames/Series arranged along the index. A Dask DataFrame is partitioned row-wise, grouping rows by index value for efficiency. These pandas objects may live on disk or on other machines. Dask DataFrame copies the pandas DataFrame API¶Because the Dask DataFrame API >>> import dask.dataframe as dd >>> df = dd.read_csv('2014-*.csv') >>> df.head() x y 0 1 a 1 2 b 2 3 c 3 4 a 4 5 b 5 6 c >>> df2 = df[df.y == 'a'].x + 1 >>> df2.compute() 0 2 3 5 Name: x, dtype: int64 pandas DataFrame API >>> import pandas as pd >>> df = pd.read_csv('2014-1.csv') >>> df.head() x y 0 1 a 1 2 b 2 3 c 3 4 a 4 5 b 5 6 c >>> df2 = df[df.y == 'a'].x + 1 >>> df2 0 2 3 5 Name: x, dtype: int64 As with all Dask collections, you trigger computation by calling the Common Uses and Anti-Uses¶Dask DataFrame is used in situations where pandas is commonly needed, usually when pandas fails due to data size or computation speed:
Dask DataFrame may not be the best choice in the following situations:
Scope¶Dask DataFrame covers a well-used portion of the pandas API. The following class of computations works well:
However, Dask DataFrame does not implement the entire pandas interface. Users expecting this will be disappointed. Notably, Dask DataFrame has the following limitations:
See the DataFrame API documentation for a more extensive list. Execution¶By default, Dask DataFrame uses the multi-threaded scheduler. This exposes some parallelism when pandas or the underlying NumPy operations release the global interpreter lock (GIL). Generally, pandas is more GIL bound than NumPy, so multi-core speed-ups are not as pronounced for Dask DataFrame as they are for Dask Array. This is particularly true for string-heavy Python DataFrames, as Python strings are GIL bound. There has been recent work on changing the underlying representation of pandas string data types to be backed by PyArrow Buffers, which should release the GIL, however, this work is still considered experimental. When dealing with text data, you may see speedups by switching to the distributed scheduler either on a cluster or single machine. When should Server Core be installed?The Server Core option is a minimal installation option that is available when you are deploying the Standard or Datacenter edition of Windows Server. Server Core includes most but not all server roles. Server Core has a smaller disk footprint, and therefore a smaller attack surface due to a smaller code base.
When installing Windows Server Why is Server Core installation recommended?Reduced management: Because fewer applications and services are installed on a server running the Server Core installation, there is less to manage. Less disk space required: A Server Core installation requires only about 1 GB of disk space to install and approximately 2 GB for operations after the installation.
What are the benefits of a Server Core installation?Benefits to using Server Core are: Reduced attack surface & improved application security environment. Reduced maintenance & management requirements. Reduced disk space & memory usage.
Which of the following role is available in the core Windows Server installation?The Server Core installation option includes the following server roles.
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Roles included in Server Core.. |