2. general topics

• A. Home
• B. Global Index

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Index

• 2. General topics
  • 2.1 GPU programming
  • 2.2 Image processing
  • 2.3 Text processing
  • 2.4 System interaction
    • 2.4.1 subprocess
    • 2.4.2 sys
  • 2.5 Printing
    • 2.5.1 Printing hacks

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2. General topics

2.1 GPU programming

2.2 Image processing

• 2.2.1 Basic processing
  • 2.2.1.1 Load image
  • 2.2.1.2 Show image
  • 2.2.1.3 Save image
• 2.2.2 Advanced processing

2.3 Text processing

2.4 System interaction

2.4.1 subprocess

The subprocess library allows to manage operative system commands. There are several ways to use it. See here

import subprocess
p = subprocess.Popen(["ls", "-l", "/etc/resolv.conf"], stdout=subprocess.PIPE)
output, err = p.communicate()
print "*** Running ls -l command ***\n", output

Output:
> *** Running ls -l command ***
> -rw-r--r-- 1 root root 157 Nov  7 15:06 /etc/resolv.conf

2.4.2 sys

• sys.path is a variable of module sys that contains the list of directories which will be searched for modules at runtime

import sys
sys.path

• Execute it from linux terminal without joining the interactive python by typing:

python -c 'import sys; print "\n".join(sys.path)'

• Check which modules are built in by typing in Python or Ipython:

import sys
sys.builtin_module_names

2.5 Printing

2.5.1 Printing Hacks

To print special unicode characters, find the code in internet and it can be printed directly

text = u'2 \u00B1 1'
Output:
2 (+-) 1

But if it pass through the str() function, it needs to be explicitly advised the encoding

text = '2 {simbol} 1'.format(simbol=u'\u00B1'.encode('utf-8'))
Output:
2 (+-) 1

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