python command prints expected changes but won't change file-CodePudding

I am using a python command to replace some string values in a txt file. Even though the 'print()' command brings the expected changes, they are not implemented in the original file.

Here is the command I am using:

inputFile = open(r'C:\Users\nigel\OneDrive\Documents\LAB\lean\03.33552_R00.txt', 'r')
lines = inputFile.readlines()
inputFile.close()
exportFile = open(r'C:\Users\nigel\OneDrive\Documents\LAB\lean\03.33552_R00.txt', 'w')

list_a=[]
list_b=[]

for line in lines:
    if 'PVObject_=pvSubArray' in line:
        list_a.append(len(list_a) 1)
    if 'PVObject_IAM=pvIAM' in line:
        list_b.append(len(list_b) 1)

list_a = [str(x) for x in list_a]
list_b = [str(x) for x in list_b]
        
print(list_a)
print(list_b)

control_a=0
control_b=0
for line in lines:
    if 'PVObject' in line:
        if 'PVObject_=pvSubArray' in line:
            new_value_a = list_a[control_a]
            control_a =1
            line = line.replace('=', new_value_a)
            line = line.strip()
            print(line)
        elif 'PVObject_IAM=pvIAM' in line:
            new_value_b = list_b[control_b]
            control_b =1
            line = line.replace('=', new_value_b)
            line = line.strip()
            print(line)
        else:
            line = line.replace('=', '')
            line = line.strip()
            print(line)

exportFile.writelines(lines[0:])
exportFile.close()

Here is the output:

['1', '2', '3', '4']
['1', '2', '3', '4']
PVObject_SiteSimulpvSite
PVObject_MeteoSimulpvMeteo
PVObject_SiteMetpvSite
PVObject_EnIncidentepvEnIncid
PVObject_PlanCapteurspvCollPlane
PVObject_PVMainArraypvMainArray
PVObject_1pvSubArray
PVObject_IAM1pvIAM
PVObject_2pvSubArray
PVObject_IAM2pvIAM
PVObject_3pvSubArray
PVObject_IAM3pvIAM
PVObject_4pvSubArray
PVObject_IAM4pvIAM
PVObject_SystempvSystem
PVObject_OmbragepvShading
PVObject_1pvShdArrayTable
PVObject_2pvShdArrayTable
PVObject_3pvShdGenObject
PVObject_4pvShdGenObject
PVObject_5pvShdGenObject
PVObject_6pvShdGenObject
PVObject_pvShdObjectGroup
PVObject_TableOmbrLin#1pvShdFTable
PVObject_ModuleLayoutpvModuleLayout
SubFields,listof2PVObjects
PVObject_1pvSubField
PVObject_2pvSubField
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot
PVObject_pvSimulPlot

As you can see from the print() output, the code does implement changes. However, nothing's changed in file '03.33552_R00.txt'. I suspect there may be some issues with the code after the last print() command:

exportFile.writelines(lines[0:])
exportFile.close()

I appreciate any help!

CodePudding user response：

lines = ['aaaa','bbb','cccc']

for line in lines:
    line ='xxxx'
    print(line) #output: xxxx

print(lines)    #output: ['aaaa', 'bbb', 'cccc']

you do not change the list lines you write into exportFile. you change line = a variable inside the loop that means nothing.

you can solve this problem with something like this:

for e, _ in enumerate(lines):
    lines[e] ='xxxx'
    print(lines)

#output:    ['xxxx', 'bbb', 'cccc']
#           ['xxxx', 'xxxx', 'cccc']
#           ['xxxx', 'xxxx', 'xxxx']

CodePudding user response：

I appreciate all the suggestions. Here is the final answer:

(...)
control_a=0
control_b=0
for i, line in enumerate(lines):
    if 'PVObject' in line:
        if 'PVObject_=pvSubArray' in line:
            new_value_a=list_a[control_a]
            control_a =1
            lines[i]=lines[i].replace('=', new_value_a)
        
        elif 'PVObject_IAM=pvIAM' in line:
            new_value_b=list_b[control_b]
            control_b =1
            lines[i]=lines[i].replace('=', new_value_b)
        
        else:
            lines[i]=lines[i].replace('=', '')

exportFile.writelines(lines[0:])
exportFile.close()