I am having a dictionary where the keys represents a coordinate (column,row) of a specific value:
d={(1,1) : value_1 , (1,2) : value_2 , (2,1) : value_3 , (2,2) : value_4}
The csv-file should only contain the values, but at the right position defined by the keys (column,row):
value_1 , value_3
value_2 , value_4
I hope anybody can give me a hint, how i could handle this one?
If you are okay using Pandas, you could use the key coordinates to directly add the dictionary values to their appropriate location, like so:
import pandas as pd
d = {
(1,1): 1,
(1,2): 2,
(2,1): 3,
(2,2): 4
}
df = pd.DataFrame()
for k, v in d.items():
df.at[k[1], k[0]] = v
df.to_csv('out.csv', index=False, header=False)
Which would output the following data table as out.csv
:
1.0,3.0
2.0,4.0
Take a look at Python's built in csv module:
https://docs.python.org/3/library/csv.html
All you need to do is:
import csv
def output_csv(input_dict, output_filename):
# translate original data dict into a list of dictionaries representing each row
output_list = []
for coord, value in input_dict.items():
while coord[1] > len(output_list):
# insert rows if the required row is not there
output_list.append({})
output_list[coord[1]-1][coord[0]] = value
# obtain the column field names
csv_fields = []
for row in output_list:
# check each row to make sure we have all the columns
if len(csv_fields) < len(row):
csv_fields = list(row)
# sort the fields in order
csv_fields.sort()
# open the output file for writing
with open(output_filename, 'w', newline='') as csvfile:
# init the csv DictWriter
writer = csv.DictWriter(csvfile,csv_fields, extrasaction='ignore',dialect='excel')
# write each row
for row in output_list:
writer.writerow(row)
d={(1,1) : 'value_1' , (1,2) : 'value_2' , (2,1) : 'value_3' , (2,2) : 'value_4'}
d2={(1,2) : 'value_2' , (2,1) : 'value_3' , (2,2) : 'value_4'}
d3={(1,3) : 'value_1' , (1,2) : 'value_2' , (2,1) : 'value_3' , (2,2) : 'value_4'}
output_csv(d, "output1.csv")
output_csv(d2, "output2.csv")
output_csv(d3, "output3.csv")
The outputs are:
output1.csv
:
value_1,value_3
value_2,value_4
output2.csv
:
,value_3
value_2,value_4
output3.csv
:
,value_3
value_2,value_4
value_1,
Another very simple approach that will solve your problem:
Say you have testread.csv with the following:
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
what you may do is:
import csv
d={(1,1) : "a" , (1,2) : "b" , (2,1) : "c" , (2,2) : "d"}
#open the file you need to modify and create a list of all rows
f = open('testread.csv', 'r')
reader = csv.reader(f)
rowlist = list(reader)
f.close()
for (k,v) in zip(d.keys(),d.values()):
rowlist[k[0]][k[1]]= v
#open the destination file and modify it
new_list = open('testwrite.csv', 'w', newline = '')
csv_writer = csv.writer(new_list)
csv_writer.writerows(rowlist)
new_list.close()
You will get the following contents for testwrite.csv:
1,2,3,4,5
1,a,b,4,5
1,c,d,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
1,2,3,4,5
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