I'm trying to write the elements in my dictionary into a text file where each key would be a column. Currently have I something that looks like
import csv
import numpy as np
data1 = np.arange(10)
data2 = np.arange(10)*2
data3 = np.arange(10)*3
writefile = '../Desktop/data.txt'
datadict = {}
datadict['data1'] = data1
datadict['data2'] = data2
datadict['data3'] = data3
f = open( writefile, 'w' )
fieldnames = ['data1','data2', 'data3']
data = csv.DictWriter(writefile, fieldnames, restval='', extrasaction='ignore', dialect='excel')
f.close()
but it gives me the error "argument 1 must have a "write" method". I'm not sure what that means. I'm also worried about the dialect = 'excel', but I'm not sure what else to put. In the end I'd like a file that has something looking like:
Thanks
No need to use DictWriter here at all:
import csv
import numpy as np
data1 = np.arange(10)
data2 = np.arange(10)*2
data3 = np.arange(10)*3
writefile = '../test.csv'
fieldnames = ['data1','data2', 'data3']
with open( writefile, 'w' ) as f:
writer = csv.writer(f)
writer.writerow(fieldnames)
writer.writerows(zip(data1, data2, data3))
You should pass the file-like object as the first argument to the DictWriter
constructor.
datalist = [{'data1': d1, 'data2': d2, 'data3': d3} for d1, d2, d3 in zip(data1, data2, data3)]
...
f = open(writefile, 'w')
...
writer = csv.DictWriter(f, ...)
for i in xrange(10):
writer.writerow(datalist[i])
f.close()
More simple analogic case:
with open(writefile, 'w') as f:
writer = csv.writer(f)
for row in zip(data1, data2, data3):
writer.writerow(row)
If you're doing the kind of data analysis it looks like you might be doing here, the best bet might be to get into pandas
, Python's dedicated data analysis library.
Here's an example which does what you want:
import pandas as pd
import numpy as np
data1 = np.arange(10)
data2 = np.arange(10)*2
data3 = np.arange(10)*3
df = pd.DataFrame(zip(data1, data2, data3), columns=['data1', 'data2', 'data3'])
df.to_csv('myfile.csv')
Pretty neat I'd say. Additionally, you can now do all sorts of unimaginable things with your data.
You can also make a DataFrame
from an existing dictionary:
In [115]: a_dict = {'foo':[1,2,3], 'bar':[4,5,6], 'baz':[7,8,9]}
In [116]: pd.DataFrame(a_dict)
Out[116]:
bar baz foo
0 4 7 1
1 5 8 2
2 6 9 3
Try this:
import csv
import numpy as np
data1 = np.arange(10)
data2 = np.arange(10)*2
data3 = np.arange(10)*3
writefile = '../Desktop/data.txt'
datadictlist = [{'data1': data1[i], 'data2': data2[i], 'data3': data3[i]} for i in xrange(10)]
f = open( writefile, 'w' )
fieldnames = ['data1','data2', 'data3']
writer = csv.DictWriter(f, fieldnames, restval='', extrasaction='ignore', dialect='excel')
writer.writerows(datadictlist)
f.close()
把'a +'代替'w'
f = open( writefile, 'a+' )
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