#!/usr/bin/env python
# coding: utf-8

# # Capturing Output With <tt>%%capture</tt>

# IPython has a [cell magic](Cell Magics.ipynb), `%%capture`, which captures the stdout/stderr of a cell. With this magic you can discard these streams or store them in a variable.

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from __future__ import print_function
import sys


# By default, `%%capture` discards these streams.  This is a simple way to suppress unwanted output.

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get_ipython().run_cell_magic('capture', '', "print('hi, stdout')\nprint('hi, stderr', file=sys.stderr)\n")


# If you specify a name, then stdout/stderr will be stored in an object in your namespace.

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get_ipython().run_cell_magic('capture', 'captured', "print('hi, stdout')\nprint('hi, stderr', file=sys.stderr)\n")


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captured


# Calling the object writes the output to stdout/stderr as appropriate.

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captured()


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captured.stdout


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captured.stderr


# `%%capture` grabs all output types, not just stdout/stderr, so you can do plots and use IPython's display system inside `%%capture`

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get_ipython().run_line_magic('matplotlib', 'inline')
import matplotlib.pyplot as plt
import numpy as np


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get_ipython().run_cell_magic('capture', 'wontshutup', '\nprint("setting up X")\nx = np.linspace(0,5,1000)\nprint("step 2: constructing y-data")\ny = np.sin(x)\nprint("step 3: display info about y")\nplt.plot(x,y)\nprint("okay, I\'m done now")\n')


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wontshutup()


# And you can selectively disable capturing stdout, stderr or rich display, by passing `--no-stdout`, `--no-stderr` and `--no-display`

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get_ipython().run_cell_magic('capture', 'cap --no-stderr', 'print(\'hi, stdout\')\nprint("hello, stderr", file=sys.stderr)\n')


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cap.stdout


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cap.stderr


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cap.outputs