tools_utilities

=Tools/Utilities= The standard library comes with a number of modules that can be used both as modules and as command-line utilities. = The //dis// Module: = The dis module is the Python disassembler. It converts byte codes to a format that is slightly more appropriate for human consumption. You can run the disassembler from the command line. It compiles the given script and prints the disassembled byte codes to the STDOUT. You can also use dis as a module. The **dis** function takes a class, method, function, or code object as its single argument.

Example:
code #!/usr/bin/python import dis

def sum: vara = 10 varb = 20

sum = vara + varb print "vara + varb = %d" % sum


 * 1) Call dis function for the function.

dis.dis(sum) code || This would produce following result: code  6           0 LOAD_CONST               1 (10) 3 STORE_FAST              0 (vara)

7          6 LOAD_CONST               2 (20) 9 STORE_FAST              1 (varb)

9         12 LOAD_FAST                0 (vara) 15 LOAD_FAST               1 (varb) 18 BINARY_ADD 19 STORE_FAST              2 (sum)

10         22 LOAD_CONST               3 ('vara + varb = %d') 25 LOAD_FAST               2 (sum) 28 BINARY_MODULO 29 PRINT_ITEM 30 PRINT_NEWLINE 31 LOAD_CONST              0 (None) 34 RETURN_VALUE code || = The //pdb// Module = The pdb module is the standard Python debugger. It is based on the bdb debugger framework. You can run the debugger from the command line (type n [or next] to go to the next line and help to get a list of available commands):

Example:
Before you try to run **pdb.py**, set your path properly to Python lib directory. So let us try with above example sum.py: code $pdb.py sum.py > /test/sum.py(3) -> import dis (Pdb) n > /test/sum.py(5) -> def sum: (Pdb) n >/test/sum.py(14) -> dis.dis(sum) (Pdb) n 6           0 LOAD_CONST               1 (10) 3 STORE_FAST              0 (vara)

7          6 LOAD_CONST               2 (20) 9 STORE_FAST              1 (varb)

9         12 LOAD_FAST                0 (vara) 15 LOAD_FAST               1 (varb) 18 BINARY_ADD 19 STORE_FAST              2 (sum)

10         22 LOAD_CONST               3 ('vara + varb = %d') 25 LOAD_FAST               2 (sum) 28 BINARY_MODULO 29 PRINT_ITEM 30 PRINT_NEWLINE 31 LOAD_CONST              0 (None) 34 RETURN_VALUE --Return-- > /test/sum.py(14) ->None -v dis.dis(sum) (Pdb) n --Return-- > (1) ->None (Pdb) code || = The //profile// Module: = The profile module is the standard Python profiler. You can run the profiler from the command line:

Example:
Let us try to profile following program: code #!/usr/bin/python

vara = 10 varb = 20

sum = vara + varb print "vara + varb = %d" % sum code || Now try running **cProfile.py** over this file //sum.py// as follows: code $cProfile.py sum.py vara + varb = 30 4 function calls in 0.000 CPU seconds

Ordered by: standard name

ncalls tottime  percall  cumtime  percall filename:lineno 1   0.000    0.000    0.000    0.000 :1   1    0.000    0.000    0.000    0.000 sum.py:3 1   0.000    0.000    0.000    0.000 {execfile} 1   0.000    0.000    0.000    0.000 {method ......} code || = The //tabnanny// Module = The tabnanny module checks Python source files for ambigous indentation. If a file mixes tabs and spaces in a way that throws off indentation, no matter what tab size you're using, the nanny complains:

Example:
<span style="background-color: #ffffff; font-family: verdana,helvetica,arial,sans-serif; font-size: 11px; text-align: justify;">Let us try to profile following program: code <span style="font-family: 'Courier New',monospace; font-size: 12px;">#!/usr/bin/python

vara = 10 varb = 20

sum = vara + varb print "vara + varb = %d" % sum code || <span style="background-color: #ffffff; font-family: verdana,helvetica,arial,sans-serif; font-size: 11px; text-align: justify;">If you would try a correct file with tabnanny.py then it won't complain as follows: code <span style="font-family: 'Courier New',monospace; font-size: 12px;">$tabnanny.py -v sum.py 'sum.py': Clean bill of health. code ||