Find number in line s.startswith python

Question

For example I have a some text fragment in file:

         Item               Value     Threshold  Converged?
 Maximum Force            0.009497     0.000450     NO 
 RMS     Force            0.002723     0.000300     NO 
 Maximum Displacement     0.247463     0.001800     NO 
 RMS     Displacement     0.065734     0.001200     NO 

 SCF Done:  E(RPW91-PW91) =  -2381.36459172     A.U. after    1 cycles

And I try to extract two numbers from columns Value and Threshold, for each lines. For example consider first line

 Maximum Force            0.009497     0.000450     NO 

So, for example I try to get the value 0.009497

#!/usr/bin/python3.6
import glob
import os


def CutMAXFValue( Line: str) -> float:
    return float(Line.split()[2]) 

def CutSCFValue( Line: str) -> float:
    return float(Line.split()[4]) 

def GrepSCF( Filename: str , StartStep = 1):
   #print(Filename)
    result = list()
    Step = StartStep
    with open(Filename, 'r') as f:
        lines = f.readlines()
    for s in lines:
        if s.startswith("SCF Done:"):
            result.append( (Step, CutSCFValue(s) ) )
            Step += 1
    return result  


def GrepMAXF( Filename: str , StartStep = 1):
   #print(Filename)
    result = list()
    Step = StartStep
    with open(Filename, 'r') as f:
        lines = f.readlines()
    for s in lines:
        if s.startswith("Maximum Force"):
            result.append( (Step, CutMAXFValue(s) ) )
            Step += 1
    return result  


def DraftListSteps(f: str):
    result = list()
    SubFiles = GetOutFilesBeginsWith( f ) #support function to read from file
    MaxRerun = GetMaxRerun( SubFiles )
    startstep = 1
    for rerun in range(MaxRerun+1):
        RFiles = GetFilesForRerun( SubFiles, rerun )
        DoneFile = next( x for x in RFiles if x.endswith("out") or x.endswith("outERR") )
        MAXF = GrepMAXF(DoneFile, startstep)
        MinStep = min(MAXF, key = lambda x: x[1] )
        startstep = MinStep[0]
        result.append(MAXF)

        # SCF = GrepSCF(DoneFile, startstep)
        # MinStep = min(MAXF, key = lambda x: x[1] )
        # startstep = MinStep[0]
        # result.append(SCF)
    return result  

And after run script I get the sam error:

Traceback (most recent call last):
  File "forker.py", line 123, in <module>
    draft = DraftListSteps( f )
  File "forker.py", line 91, in DraftListSteps
    MinStep = min(MAXF, key = lambda x: x[1] )
ValueError: min() arg is an empty sequence

How to fix this error and extract required value? So, regexp don't work in tis case, thoug maybe I wrong code pattern for regexp...

If I exctract value of -2381.36459172 from SCF Done fragment this code work perfectly, but if I use code for get 0.009497 it's not work...

Answer 1

I'll bet anything it's a TAB between Maximum and Force, so change

if s.startswith("Maximum Force"):

to

if s.startswith("Maximum\tForce"):

Or you can handle either with a regular expression:

if re.match(r'Maximum\s+Force', s):