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1 """
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2 # oct 2009 - must make a map file in case later usage requires it...
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3 # galaxy tool xml files can define a galaxy supplied output filename
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4 # that must be passed to the tool and used to return output
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5 # here, the plink log file is copied to that file and removed
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6 # took a while to figure this out!
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7 # use exec_before_job to give files sensible names
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8 #
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9 # ross april 14 2007
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10 # plink cleanup script
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11 # ross lazarus March 2007 for camp illumina whole genome data
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12 # note problems with multiple commands being ignored - eg --freq --missing --mendel
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13 # only the first seems to get done...
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14 #
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15 ##Summary statistics versus inclusion criteria
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16 ##
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17 ##Feature As summary statistic As inclusion criteria
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18 ##Missingness per individual --missing --mind N
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19 ##Missingness per marker --missing --geno N
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20 ##Allele frequency --freq --maf N
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21 ##Hardy-Weinberg equilibrium --hardy --hwe N
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22 ##Mendel error rates --mendel --me N M
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23 #
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24 # this is rgLDIndep.py - main task is to decrease LD by filtering high LD pairs
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25 # remove that function from rgClean.py as it may not be needed.
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26
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27 """
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28 import sys,shutil,os,subprocess, glob, string, tempfile, time
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29 from rgutils import plinke, timenow, galhtmlprefix
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30
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31 prog = os.path.split(sys.argv[0])[-1]
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32 myversion = 'January 4 2010'
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33
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34
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35 def pruneld(plinktasks=[] ,cd='./',vclbase = []):
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36 """
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37 plink blathers when doing pruning - ignore
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38 Linkage disequilibrium based SNP pruning
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39 if a million snps in 3 billion base pairs, have mean 3k spacing
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40 assume 40-60k of ld in ceu, a window of 120k width is about 40 snps
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41 so lots more is perhaps less efficient - each window computational cost is
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42 ON^2 unless the code is smart enough to avoid unecessary computation where
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43 allele frequencies make it impossible to see ld > the r^2 cutoff threshold
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44 So, do a window and move forward 20?
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45 from the plink docs at http://pngu.mgh.harvard.edu/~purcell/plink/summary.shtml#prune
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46
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47 Sometimes it is useful to generate a pruned subset of SNPs that are in approximate linkage equilibrium with each other. This can be achieved via two commands: --indep which prunes based on the variance inflation factor (VIF), which recursively removes SNPs within a sliding window; second, --indep-pairwise which is similar, except it is based only on pairwise genotypic correlation.
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48
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49 Hint The output of either of these commands is two lists of SNPs: those that are pruned out and those that are not. A separate command using the --extract or --exclude option is necessary to actually perform the pruning.
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50
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51 The VIF pruning routine is performed:
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52 plink --file data --indep 50 5 2
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53
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54 will create files
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55
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56 plink.prune.in
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57 plink.prune.out
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58
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59 Each is a simlpe list of SNP IDs; both these files can subsequently be specified as the argument for
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60 a --extract or --exclude command.
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61
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62 The parameters for --indep are: window size in SNPs (e.g. 50), the number of SNPs to shift the
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63 window at each step (e.g. 5), the VIF threshold. The VIF is 1/(1-R^2) where R^2 is the multiple correlation coefficient for a SNP being regressed on all other SNPs simultaneously. That is, this considers the correlations between SNPs but also between linear combinations of SNPs. A VIF of 10 is often taken to represent near collinearity problems in standard multiple regression analyses (i.e. implies R^2 of 0.9). A VIF of 1 would imply that the SNP is completely independent of all other SNPs. Practically, values between 1.5 and 2 should probably be used; particularly in small samples, if this threshold is too low and/or the window size is too large, too many SNPs may be removed.
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64
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65 The second procedure is performed:
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66 plink --file data --indep-pairwise 50 5 0.5
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67
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68 This generates the same output files as the first version; the only difference is that a
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69 simple pairwise threshold is used. The first two parameters (50 and 5) are the same as above (window size and step); the third parameter represents the r^2 threshold. Note: this represents the pairwise SNP-SNP metric now, not the multiple correlation coefficient; also note, this is based on the genotypic correlation, i.e. it does not involve phasing.
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70
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71 To give a concrete example: the command above that specifies 50 5 0.5 would a) consider a
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72 window of 50 SNPs, b) calculate LD between each pair of SNPs in the window, b) remove one of a pair of SNPs if the LD is greater than 0.5, c) shift the window 5 SNPs forward and repeat the procedure.
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73
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74 To make a new, pruned file, then use something like (in this example, we also convert the
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75 standard PED fileset to a binary one):
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76 plink --file data --extract plink.prune.in --make-bed --out pruneddata
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77 """
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78 logres = ['## Rgenetics %s: http://rgenetics.org Galaxy Tools rgLDIndep.py Plink pruneLD runner\n' % myversion,]
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79 for task in plinktasks: # each is a list
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80 fplog,plog = tempfile.mkstemp()
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81 sto = open(plog,'w') # to catch the blather
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82 vcl = vclbase + task
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83 s = '## ldindep now executing %s\n' % ' '.join(vcl)
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84 print s
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85 logres.append(s)
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86 x = subprocess.Popen(' '.join(vcl),shell=True,stdout=sto,stderr=sto,cwd=cd)
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87 retval = x.wait()
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88 sto.close()
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89 sto = open(plog,'r') # read
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90 try:
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91 lplog = sto.readlines()
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92 lplog = [x for x in lplog if x.find('Pruning SNP') == -1]
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93 logres += lplog
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94 logres.append('\n')
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95 except:
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96 logres.append('### %s Strange - no std out from plink when running command line\n%s' % (timenow(),' '.join(vcl)))
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97 sto.close()
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98 os.unlink(plog) # no longer needed
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99 return logres
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100
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101
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102
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103 def clean():
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104 """
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105 """
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106 if len(sys.argv) < 14:
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107 print >> sys.stdout, '## %s expected 14 params in sys.argv, got %d - %s' % (prog,len(sys.argv),sys.argv)
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108 print >> sys.stdout, """this script will filter a linkage format ped
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109 and map file containing genotypes. It takes 14 parameters - the plink --f parameter and"
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110 a new filename root for the output clean data followed by the mind,geno,hwe,maf, mef and mei"
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111 documented in the plink docs plus the file to be returned to Galaxy
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112 Called as:
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113 <command interpreter="python">
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114 rgLDIndep.py '$input_file.extra_files_path' '$input_file.metadata.base_name' '$title' '$mind'
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115 '$geno' '$hwe' '$maf' '$mef' '$mei' '$out_file1'
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116 '$out_file1.extra_files_path' '$window' '$step' '$r2'
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117 </command>
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118 """
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119 sys.exit(1)
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120 plog = ['## Rgenetics: http://rgenetics.org Galaxy Tools rgLDIndep.py started %s\n' % timenow()]
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121 inpath = sys.argv[1]
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122 inbase = sys.argv[2]
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123 killme = string.punctuation + string.whitespace
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124 trantab = string.maketrans(killme,'_'*len(killme))
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125 title = sys.argv[3].translate(trantab)
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126 mind = sys.argv[4]
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127 geno = sys.argv[5]
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128 hwe = sys.argv[6]
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129 maf = sys.argv[7]
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130 me1 = sys.argv[8]
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131 me2 = sys.argv[9]
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132 outfname = sys.argv[10]
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133 outfpath = sys.argv[11]
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134 winsize = sys.argv[12]
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135 step = sys.argv[13]
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136 r2 = sys.argv[14]
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137 output = os.path.join(outfpath,outfname)
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138 outpath = os.path.join(outfpath,title)
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139 outprunepath = os.path.join(outfpath,'ldprune_%s' % title)
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140 try:
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141 os.makedirs(outfpath)
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142 except:
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143 pass
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144 bfile = os.path.join(inpath,inbase)
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145 filterout = os.path.join(outpath,'filtered_%s' % inbase)
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146 outf = file(outfname,'w')
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147 outf.write(galhtmlprefix % prog)
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148 ldin = bfile
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149 plinktasks = [['--bfile',ldin,'--indep-pairwise %s %s %s' % (winsize,step,r2),'--out',outpath,
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150 '--mind',mind,'--geno',geno,'--maf',maf,'--hwe',hwe,'--me',me1,me2,],
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151 ['--bfile',ldin,'--extract %s.prune.in --make-bed --out %s' % (outpath,outpath)],
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152 ['--bfile',outpath,'--recode --out',outpath]] # make map file - don't really need ped but...
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153 # subset of ld independent markers for eigenstrat and other requirements
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154 vclbase = [plinke,'--noweb']
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155 prunelog = pruneld(plinktasks=plinktasks,cd=outfpath,vclbase = vclbase)
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156 """This generates the same output files as the first version;
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157 the only difference is that a simple pairwise threshold is used.
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158 The first two parameters (50 and 5) are the same as above (window size and step);
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159 the third parameter represents the r^2 threshold.
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160 Note: this represents the pairwise SNP-SNP metric now, not the
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161 multiple correlation coefficient; also note, this is based on the
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162 genotypic correlation, i.e. it does not involve phasing.
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163 """
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164 plog += prunelog
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165 flog = '%s.log' % outpath
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166 flogf = open(flog,'w')
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167 flogf.write(''.join(plog))
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168 flogf.write('\n')
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169 flogf.close()
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170 globme = os.path.join(outfpath,'*')
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171 flist = glob.glob(globme)
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172 flist.sort()
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173 for i, data in enumerate( flist ):
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174 outf.write('<li><a href="%s">%s</a></li>\n' % (os.path.split(data)[-1],os.path.split(data)[-1]))
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175 outf.write('</ol></div>\n')
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176 outf.write("</div></body></html>")
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177 outf.close()
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178
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179
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180 if __name__ == "__main__":
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181 clean()
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182
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