cpython: f2a73d65422a (original) (raw)

--- a/Doc/library/csv.rst +++ b/Doc/library/csv.rst @@ -419,32 +419,36 @@ Examples The simplest example of reading a CSV file:: import csv

reader = csv.reader(open("some.csv", newline=''))
for row in reader:
```
  print(row)[](#l1.9)
```

with open('some.csv', newline='') as f:
```
  reader = csv.reader(f)[](#l1.11)
```
```
  for row in reader:[](#l1.12)
```
```
      print(row)[](#l1.13)
```

Reading a file with an alternate format:: import csv

reader = csv.reader(open("passwd"), delimiter=':', quoting=csv.QUOTE_NONE)
for row in reader:
```
  print(row)[](#l1.20)
```

with open('passwd') as f:

  reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)[](#l1.22)

```
  for row in reader:[](#l1.23)
```
```
      print(row)[](#l1.24)
```

The corresponding simplest possible writing example is:: import csv

writer = csv.writer(open("some.csv", "w"))
writer.writerows(someiterable)

with open('some.csv', 'w') as f:
```
  writer = csv.writer(f)[](#l1.32)
```

  writer.writerows(someiterable)[](#l1.33)

Since :func:open is used to open a CSV file for reading, the file will by default be decoded into unicode using the system default encoding (see :func:locale.getpreferredencoding). To decode a file using a different encoding, use the encoding argument of open::

import csv
reader = csv.reader(open("some.csv", newline='', encoding='utf-8'))
for row in reader:
```
   print(row)[](#l1.43)
```

import csv
with open('some.csv', newline='', encoding='utf-8') as f:
```
  reader = csv.reader(f)[](#l1.46)
```
```
  for row in reader:[](#l1.47)
```
```
      print(row)[](#l1.48)
```

The same applies to writing in something other than the system default encoding: specify the encoding argument when opening the output file. @@ -453,18 +457,20 @@ Registering a new dialect:: import csv csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)

reader = csv.reader(open("passwd"), 'unixpwd')

with open('passwd') as f:

  reader = csv.reader(f, 'unixpwd')[](#l1.58)

A slightly more advanced use of the reader --- catching and reporting errors:: import csv, sys

filename = "some.csv"
reader = csv.reader(open(filename, newline=''))
try:
```
  for row in reader:[](#l1.66)
```
```
      print(row)[](#l1.67)
```
except csv.Error as e:

  sys.exit('file {}, line {}: {}'.format(filename, reader.line_num, e))[](#l1.69)

filename = 'some.csv'
with open(filename, newline='') as f:
```
  reader = csv.reader(f)[](#l1.72)
```
```
  try:[](#l1.73)
```
```
      for row in reader:[](#l1.74)
```
```
          print(row)[](#l1.75)
```
```
  except csv.Error as e:[](#l1.76)
```

      sys.exit('file {}, line {}: {}'.format(filename, reader.line_num, e))[](#l1.77)

And while the module doesn't directly support parsing strings, it can easily be done::