Python csv module, pythoncsv

Python csv module, pythoncsv

1 import csv # Comma Separated Value 2 3 # class Dialect 4 # delimiter = None # separator 5 # doublequote = None # The element is a quote, double the quote. The default value is true. If it is set to false, you need to set the delimiter. Otherwise, an error is returned. 6 # escapechar = None # Escape Character 7 # lineterminator = None # line terminator 8 # quotechar = None # reference character 9 # quoting = None # reference method 10 # skipinitialspace = None # ignore split the space behind, the default value is flase 11 #12 #13 # QUOTE_ALL = 1 # full quotation marks 14 # QUOTE_MINIMAL = 0 # delimiter and reference symbol plus double quotation marks 15 # QUOTE_NONE = 3 # All without double quotation marks, escape Character 16 # QUOTE_NONNUMERIC = 2 # number without quotation marks 17 #18 # csv. QUOTE_MINIMAL means only when required, for example, when a field contains either the quotechar or the delimiter 19 # csv. QUOTE_ALL means that quotes are always placed around fields. 20 # csv. QUOTE_NONNUMERIC means that quotes are always placed und fields which do not parse as integers or floating point numbers. 21 # csv. QUOTE_NONE means that quotes are never placed around fields. 22 23 24 #1. Write a csv file quoting = csv. QUOTE_ALL 25 with open ("1.csv"," w ", newline =" ") as f: 26 # dialect is used to open a csv file. The default value is excel, the delimiter = "\ t" parameter indicates the delimiter 27 # csv_writer = csv. writer (f, dialect = "excel-tab") 28 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 29 csv_writer = csv. writer (f, dialect = "excel", quoting = csv. QUOTE_ALL) 30 # insert A row of data into the csv file and put each item in the following list into A cell (multiple rows can be inserted cyclically) 31 csv_writer.writerow (["A", "B ", ",", 5]) 32 csv_writer.writerow (["E", "F", '"', 6]) 33 34 with open (" 1.csv", "rb ") as f: 35 print (f. read () 36 # B '"A", "B", "5" \ r \ n "E", "F ","""", "6" \ r \ n' 37 38 with open ("1.csv"," r ") as f: 39 print (f. read () 40 # "A", "B", "5" 41 # "E 42 43 #2. Write A csv file quoting = csv. QUOTE_MINIMAL 44 with open ("2.csv"," w ", newline =" ") as f: 45 # dialect indicates how to open a csv file. The default value is excel, the delimiter = "\ t" parameter indicates the delimiter 46 # csv_writer = csv. writer (f, dialect = "excel-tab") 47 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 48 csv_writer = csv. writer (f, dialect = "excel", quoting = csv. QUOTE_MINIMAL) 49 # insert A row of data into the csv file and put each item in the following list into A cell (multiple rows can be inserted cyclically) 50 csv_writer.writerow (["A", "B ", ",", 5]) 51 csv_writer.writerow (["E", "F", '"', 6]) 52 53 with open (" 2.csv", "rb ") as f: 54 print (f. read () 55 # B 'A, B, ",", 5 \ r \ nE, F ,"""", 6 \ r \ n' 56 57 with open ("2.csv"," r ") as f: 58 print (f. read () 59 # A, B, ",", 5 60 # E, F ,"""", 6 61 62 63 #3. Write a csv file quoting = csv. QUOTE_NONE 64 with open ("3.csv"," w ", newline =" ") as f: 65 # dialect is used to open a csv file. The default value is excel, the delimiter = "\ t" parameter indicates the delimiter 66 # csv_writer = csv. writer (f, dialect = "excel-tab") 67 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 68 csv_writer = csv. writer (f, dialect = "excel", quoting = csv. QUOTE_NONE, escapechar = '\') # This method requires an escape character 69 # insert a row of data into the csv file, put each item in the following list into A cell (multiple rows can be inserted cyclically) 70 csv_writer.writerow (["A", "B", 5]) 71 csv_writer.writerow (["E", "F", '"', 6]) 72 73 with open (" 3.csv", "rb") as f: 74 print (f. read () 75 # B 'A, B, \\,, 5 \ r \ nE, F ,\\", 6 \ r \ n' 76 77 with open ("3.csv"," r ") as f: 78 print (f. read () 79 # A, B, \, 5 80 # E, F, \ ", 6 81 82 83 #4. Write A csv file quoting = csv. QUOTE_NONNUMERIC 84 with open ("4.csv"," w ", newline =" ") as f: 85 # dialect is used to open a csv file. The default value is excel, delimiter = "\ t" parameter indicates the delimiter 86 # csv_writer = csv when writing. writer (f, dialect = "excel-tab") 87 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 88 csv_writer = csv. writer (f, dialect = "excel", quoting = csv. QUOTE_NONNUMERIC) 89 # insert A row of data into the csv file and put each item in the following list into A cell (multiple rows can be inserted cyclically) 90 csv_writer.writerow (["A", "B ", ",", 5]) 91 csv_writer.writerow (["E", "F", '"', 6]) 92 93 with open (" 4.csv", "rb ") as f: 94 print (f. read () 95 # B '"A", "B", 5 \ r \ n "E", "F ","""", 6 \ r \ n' 96 97 with open ("4.csv"," r ") as f: 98 print (f. read () 99 # "A", "B", 5100 # "E", "F ","""", 6101 102 103 #5. Write a csv file quoting = default (quoting = csv. QUOTE_MINIMAL) 104 with open ("5.csv"," w ", newline =" ") as f: 105 # dialect is used to open a csv file. The default value is excel, the delimiter = "\ t" parameter indicates the delimiter 106 # csv_writer = csv. writer (f, dialect = "excel-tab") 107 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 108 csv_writer = csv. writer (f, dialect = "excel") 109 # insert a row of data into the csv file and put each item in the following list into a cell (multiple rows can be inserted in a loop) 110 csv_writer.writerow (["A", "B", 5]) 111 csv_writer.writerow (["E", "F", '"', 6]) 112 113 with open ("5.csv"," rb ") as f: 114 print (f. read () 115 # B 'A, B, ",", 5 \ r \ nE, F ,"""", 6 \ r \ n' 116 117 with open ("5.csv"," r ") as f: 118 print (f. read () 119 # A, B, ",", 5120 # E, F ,"""", 6121 122 #6. Write a csv file 123 with open ("6.csv"," w ", newline =" ") as f: 124 # dialect is used to open a csv file, the default value is excel. The delimiter = "\ t" parameter indicates the delimiter 126 # csv_writer = csv when writing. writer (f, dialect = "excel-tab") 127 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 128 csv_writer = csv. writer (f) 129 # insert A row of data into the csv file and put each item in the following list into A cell (multiple rows can be inserted cyclically) 130 csv_writer.writerow (["", "B", 5]) 131 csv_writer.writerow (["E", "F", '"', 6]) 132 133 with open (" 6.csv ", "rb") as f: 134 print (f. read () 135 # B 'A, B, ",", 5 \ r \ nE, F ,"""", 6 \ r \ n' 136 137 with open ("6.csv"," r ") as f: 138 print (f. read () 139 # A, B, ",", 5140 # E, F, ", 6141 142 143 #7. Registration style 144 csv. register_dialect ('mystyle', delimiter = ',', quoting = csv. QUOTE_MINIMAL) 145 with open ("7.csv"," w ", newline =" ") as f: 146 # dialect is used to open a csv file. The default value is excel, the delimiter = "\ t" parameter indicates the delimiter 147 # csv_writer = csv. writer (f, dialect = "excel-tab") 148 # csv_writer = csv. writer (f, dialect = "excel", delimiter = "\ t") 149 csv_writer = csv. writer (f, dialect = "mystyle") 150 # insert a row of data into the csv file and put each item in the following list into a cell (multiple rows can be inserted cyclically) 151 csv_writer.writerow (["A", "B", 5]) 152 csv_writer.writerow (["E", "F", '", 6]) 153 154 with open ("7.csv"," rb ") as f: 155 print (f. read () 156 # B 'A, B, ",", 5 \ r \ nE, F ,"""""""", 6 \ r \ n' 157 158 with open ("7.csv"," r ") as f: 159 print (f. read () 160 # A, B, ",", 5161 # E, F ,"""""""", 6162 163 164 #8. Read the csv file 165 csv. register_dialect ('mystyle', delimiter = ',', quoting = csv. QUOTE_MINIMAL) 166 with open('7.csv ', newline = '') as f: 167 reader = csv. reader (f, 'mystyle') 168 for r in reader: 169 print (r, type (r) 170 # ['A', 'B ',',', '5'] <class 'LIST'> 171 # ['E', 'F ','"', '6'] <class 'LIST'> 172 173 174 #9. Read the csv file 175 for row in csv. reader (['one, two, three ', 'one, two, three'], skipinitialspace = True): # skipinitialspace ignore space 176 print (row, type (row )) 177 # ['one', 'two', 'three '] <class 'LIST'> 178 # ['one', 'two ', 'Three '] <class 'LIST'> 179 180 181 #10, DictWriter182 with open('8.csv', 'w', newline = '') as csv_file: 183 fieldnames = ['first _ name', 'last _ name'] 184 writer = csv. dictWriter (csv_file, fieldnames = fieldnames) 185 186 writer. writeheader () 187 writer. writerow ({'first _ name': 'bak', 'last _ name': 'beans '}) 188 writer. writerow ({'first _ name': 'lovely', 'last _ name': 'spam'}) 189 writer. writerow ({'first _ name': 'Wonderful ', 'last _ name': 'spam'}) 190 writer. writerows ([{'first _ name': 'Wonderful ', 'last _ name': 'spam'}, {'first _ name': 'Wonderful ', 'Last _ name': 'spam'}]) 191 192 #11. DictReader193 with open('8.csv ', newline = '') as csv_file: 194 reader = csv. dictReader (csv_file) 195 for row in reader: 196 print (row) # OrderedDict ([('first _ name', 'bak'), ('Last _ name ', 'beans ')]) 197 print (row ['first _ name'], row ['last _ name'])