Difference between revisions of "Python/scripts"
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==Selective printing== | ==Selective printing== | ||
*Print every 4th character of the English alphabet starting with the letter/character 'c': | *Print every 4th character of the English alphabet starting with the letter/character 'c': | ||
+ | >>> import string | ||
+ | >>> string.ascii_letters | ||
+ | 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' | ||
+ | >>> string.ascii_letters[0:26] | ||
+ | 'abcdefghijklmnopqrstuvwxy' | ||
+ | |||
alpha_lc = map(chr, range(97, 123)) | alpha_lc = map(chr, range(97, 123)) | ||
alpha_lc = [chr(i) for i in xrange(ord('a'), ord('z')+1)] | alpha_lc = [chr(i) for i in xrange(ord('a'), ord('z')+1)] |
Revision as of 20:04, 14 June 2012
This article will list a bunch of quick-and-dirty Python tips-and-tricks, examples, code, etc.
Contents
Generate a random set of characters
Note: Useful for creating random user passwords after a reset.
$ python -c 'import random; print "".join([random.choice("abcdefghijklmnopqrstuvwxyz0123456789\!@#$%^&*(-_=+)") for i in range(9)])'
Lambda functions
In stead of creating a new function of
f(x): return x + 1
You could use a lambda function inline, like so:
function_var = lambda x: x + 1 >>> print function_var(2) 3
Selective printing
- Print every 4th character of the English alphabet starting with the letter/character 'c':
>>> import string >>> string.ascii_letters 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' >>> string.ascii_letters[0:26] 'abcdefghijklmnopqrstuvwxy'
alpha_lc = map(chr, range(97, 123)) alpha_lc = [chr(i) for i in xrange(ord('a'), ord('z')+1)] alpha_uc = map(chr, range(65, 91)) alpha_ns = 'abcdefghijklmnopqrstuvwxyz' alpha_sp = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'] >>> alpha_ns[2::4] # Method 1 'cgkosw' >>> [alpha_lc[i] for i in range(2, len(alpha_lc), 4)] # Method 2 ['c', 'g', 'k', 'o', 's', 'w'] >>> map(chr, range(97, 123))[2::4] # Method 3 (one-liner) ['c', 'g', 'k', 'o', 's', 'w']
Iterative printing
- Input:
data = [1,2,3,4,5,6]
- Methods:
for i,k in zip(data[0::2], data[1::2]): print str(i), '+', str(k), '=', str(i+k) # ~OR~ for i in range(0, len(l), 2): print str(l[i]), '+', str(l[i + 1]), '=', str(l[i] + l[i + 1])
- Output:
1 + 2 = 3 3 + 4 = 7 5 + 6 = 11
- Other
l = [1,2,3,4,5,6] >>> zip(l, l[1:]) [(1, 2), (2, 3), (3, 4), (4, 5), (5, 6)] >>> zip(l, l[1:])[::2] [(1, 2), (3, 4), (5, 6)] >>> [a+b for a,b in zip(l, l[1:])[::2]] [3, 7, 11] >>> ["%d + %d = %d" % (a, b, a+b) for a,b in zip(l, l[1:])[::2]] ['1 + 2 = 3', '3 + 4 = 7', '5 + 6 = 11'] >>> list = '1234567890' >>> n = 2 >>> [list[i:i+n] for i in range(0, len(list), n)] ['12', '34', '56', '78', '90'] # The following two accomplish the same thing: >>> map(''.join, zip(*[iter(list)]*2)) >>> re.findall('..', list)