Tuesday, 30 June 2020

Python : Pandas - 4



#set values of "am" column to 1
cars['am'] = 1
cars
Out[33]:
Unnamed: 0
mpg
cyl
disp
hp
drat
wt
qsec
vs
am
gear
carb
0
Mazda RX4
21.0
6
160.0
110
3.90
2.620
16.46
0
1
4
4
1
Mazda RX4 Wag
21.0
6
160.0
110
3.90
2.875
17.02
0
1
4
4
2
Datsun 710
22.8
4
108.0
93
3.85
2.320
18.61
1
1
4
1
3
Hornet 4 Drive
21.4
6
258.0
110
3.08
3.215
19.44
1
1
3
1
4
Hornet Sportabout
18.7
8
360.0
175
3.15
3.440
17.02
0
1
3
2
5
Valiant
18.1
6
225.0
105
2.76
3.460
20.22
1
1
3
1
6
Duster 360
14.3
8
360.0
245
3.21
3.570
15.84
0
1
3
4
7
Merc 240D
24.4
4
146.7
62
3.69
3.190
20.00
1
1
4
2
8
Merc 230
22.8
4
140.8
95
3.92
3.150
22.90
1
1
4
2
9
Merc 280
19.2
6
167.6
123
3.92
3.440
18.30
1
1
4
4
10
Merc 280C
17.8
6
167.6
123
3.92
3.440
18.90
1
1
4
4
11
Merc 450SE
16.4
8
275.8
180
3.07
4.070
17.40
0
1
3
3
12
Merc 450SL
17.3
8
275.8
180
3.07
3.730
17.60
0
1
3
3
13
Merc 450SLC
15.2
8
275.8
180
3.07
3.780
18.00
0
1
3
3
14
Cadillac Fleetwood
10.4
8
472.0
205
2.93
5.250
17.98
0
1
3
4
15
Lincoln Continental
10.4
8
460.0
215
3.00
5.424
17.82
0
1
3
4
16
Chrysler Imperial
14.7
8
440.0
230
3.23
5.345
17.42
0
1
3
4
17
Fiat 128
32.4
4
78.7
66
4.08
2.200
19.47
1
1
4
1
18
Honda Civic
30.4
4
75.7
52
4.93
1.615
18.52
1
1
4
2
19
Toyota Corolla
33.9
4
71.1
65
4.22
1.835
19.90
1
1
4
1
20
Toyota Corona
21.5
4
120.1
97
3.70
2.465
20.01
1
1
3
1
21
Dodge Challenger
15.5
8
318.0
150
2.76
3.520
16.87
0
1
3
2
22
AMC Javelin
15.2
8
304.0
150
3.15
3.435
17.30
0
1
3
2
23
Camaro Z28
13.3
8
350.0
245
3.73
3.840
15.41
0
1
3
4
24
Pontiac Firebird
19.2
8
400.0
175
3.08
3.845
17.05
0
1
3
2
25
Fiat X1-9
27.3
4
79.0
66
4.08
1.935
18.90
1
1
4
1
26
Porsche 914-2
26.0
4
120.3
91
4.43
2.140
16.70
0
1
5
2
27
Lotus Europa
30.4
4
95.1
113
3.77
1.513
16.90
1
1
5
2
28
Ford Pantera L
15.8
8
351.0
264
4.22
3.170
14.50
0
1
5
4
29
Ferrari Dino
19.7
6
145.0
175
3.62
2.770
15.50
0
1
5
6
30
Maserati Bora
15.0
8
301.0
335
3.54
3.570
14.60
0
1
5
8
31
Volvo 142E
21.4
4
121.0
109
4.11
2.780
18.60
1
1
4
2
. . .

# tripple the value of "carb" using lambda function
cars2=cars
cars2
f = lambda x: x*3
cars2['carb'] = cars2['carb'].apply(f)
cars2

Out[34]:
Unnamed: 0
mpg
cyl
disp
hp
drat
wt
qsec
vs
am
gear
carb
0
Mazda RX4
21.0
6
160.0
110
3.90
2.620
16.46
0
1
4
12
1
Mazda RX4 Wag
21.0
6
160.0
110
3.90
2.875
17.02
0
1
4
12
2
Datsun 710
22.8
4
108.0
93
3.85
2.320
18.61
1
1
4
3
3
Hornet 4 Drive
21.4
6
258.0
110
3.08
3.215
19.44
1
1
3
3
4
Hornet Sportabout
18.7
8
360.0
175
3.15
3.440
17.02
0
1
3
6
5
Valiant
18.1
6
225.0
105
2.76
3.460
20.22
1
1
3
3
6
Duster 360
14.3
8
360.0
245
3.21
3.570
15.84
0
1
3
12
7
Merc 240D
24.4
4
146.7
62
3.69
3.190
20.00
1
1
4
6
8
Merc 230
22.8
4
140.8
95
3.92
3.150
22.90
1
1
4
6
9
Merc 280
19.2
6
167.6
123
3.92
3.440
18.30
1
1
4
12
10
Merc 280C
17.8
6
167.6
123
3.92
3.440
18.90
1
1
4
12
11
Merc 450SE
16.4
8
275.8
180
3.07
4.070
17.40
0
1
3
9
12
Merc 450SL
17.3
8
275.8
180
3.07
3.730
17.60
0
1
3
9
13
Merc 450SLC
15.2
8
275.8
180
3.07
3.780
18.00
0
1
3
9
14
Cadillac Fleetwood
10.4
8
472.0
205
2.93
5.250
17.98
0
1
3
12
15
Lincoln Continental
10.4
8
460.0
215
3.00
5.424
17.82
0
1
3
12
16
Chrysler Imperial
14.7
8
440.0
230
3.23
5.345
17.42
0
1
3
12
17
Fiat 128
32.4
4
78.7
66
4.08
2.200
19.47
1
1
4
3
18
Honda Civic
30.4
4
75.7
52
4.93
1.615
18.52
1
1
4
6
19
Toyota Corolla
33.9
4
71.1
65
4.22
1.835
19.90
1
1
4
3
20
Toyota Corona
21.5
4
120.1
97
3.70
2.465
20.01
1
1
3
3
21
Dodge Challenger
15.5
8
318.0
150
2.76
3.520
16.87
0
1
3
6
22
AMC Javelin
15.2
8
304.0
150
3.15
3.435
17.30
0
1
3
6
23
Camaro Z28
13.3
8
350.0
245
3.73
3.840
15.41
0
1
3
12
24
Pontiac Firebird
19.2
8
400.0
175
3.08
3.845
17.05
0
1
3
6
25
Fiat X1-9
27.3
4
79.0
66
4.08
1.935
18.90
1
1
4
3
26
Porsche 914-2
26.0
4
120.3
91
4.43
2.140
16.70
0
1
5
6
27
Lotus Europa
30.4
4
95.1
113
3.77
1.513
16.90
1
1
5
6
28
Ford Pantera L
15.8
8
351.0
264
4.22
3.170
14.50
0
1
5
12
29
Ferrari Dino
19.7
6
145.0
175
3.62
2.770
15.50
0
1
5
18
30
Maserati Bora
15.0
8
301.0
335
3.54
3.570
14.60
0
1
5
24
31
Volvo 142E
21.4
4
121.0
109
4.11
2.780
18.60
1
1
4
6
. . .
 cars
Out[35]:
Unnamed: 0
mpg
cyl
disp
hp
drat
wt
qsec
vs
am
gear
carb
0
Mazda RX4
21.0
6
160.0
110
3.90
2.620
16.46
0
1
4
12
1
Mazda RX4 Wag
21.0
6
160.0
110
3.90
2.875
17.02
0
1
4
12
2
Datsun 710
22.8
4
108.0
93
3.85
2.320
18.61
1
1
4
3
3
Hornet 4 Drive
21.4
6
258.0
110
3.08
3.215
19.44
1
1
3
3
4
Hornet Sportabout
18.7
8
360.0
175
3.15
3.440
17.02
0
1
3
6
5
Valiant
18.1
6
225.0
105
2.76
3.460
20.22
1
1
3
3
6
Duster 360
14.3
8
360.0
245
3.21
3.570
15.84
0
1
3
12
7
Merc 240D
24.4
4
146.7
62
3.69
3.190
20.00
1
1
4
6
8
Merc 230
22.8
4
140.8
95
3.92
3.150
22.90
1
1
4
6
9
Merc 280
19.2
6
167.6
123
3.92
3.440
18.30
1
1
4
12
10
Merc 280C
17.8
6
167.6
123
3.92
3.440
18.90
1
1
4
12
11
Merc 450SE
16.4
8
275.8
180
3.07
4.070
17.40
0
1
3
9
12
Merc 450SL
17.3
8
275.8
180
3.07
3.730
17.60
0
1
3
9
13
Merc 450SLC
15.2
8
275.8
180
3.07
3.780
18.00
0
1
3
9
14
Cadillac Fleetwood
10.4
8
472.0
205
2.93
5.250
17.98
0
1
3
12
15
Lincoln Continental
10.4
8
460.0
215
3.00
5.424
17.82
0
1
3
12
16
Chrysler Imperial
14.7
8
440.0
230
3.23
5.345
17.42
0
1
3
12
17
Fiat 128
32.4
4
78.7
66
4.08
2.200
19.47
1
1
4
3
18
Honda Civic
30.4
4
75.7
52
4.93
1.615
18.52
1
1
4
6
19
Toyota Corolla
33.9
4
71.1
65
4.22
1.835
19.90
1
1
4
3
20
Toyota Corona
21.5
4
120.1
97
3.70
2.465
20.01
1
1
3
3
21
Dodge Challenger
15.5
8
318.0
150
2.76
3.520
16.87
0
1
3
6
22
AMC Javelin
15.2
8
304.0
150
3.15
3.435
17.30
0
1
3
6
23
Camaro Z28
13.3
8
350.0
245
3.73
3.840
15.41
0
1
3
12
24
Pontiac Firebird
19.2
8
400.0
175
3.08
3.845
17.05
0
1
3
6
25
Fiat X1-9
27.3
4
79.0
66
4.08
1.935
18.90
1
1
4
3
26
Porsche 914-2
26.0
4
120.3
91
4.43
2.140
16.70
0
1
5
6
27
Lotus Europa
30.4
4
95.1
113
3.77
1.513
16.90
1
1
5
6
28
Ford Pantera L
15.8
8
351.0
264
4.22
3.170
14.50
0
1
5
12
29
Ferrari Dino
19.7
6
145.0
175
3.62
2.770
15.50
0
1
5
18
30
Maserati Bora
15.0
8
301.0
335
3.54
3.570
14.60
0
1
5
24
31
Volvo 142E
21.4
4
121.0
109
4.11
2.780
18.60
1
1
4
6
. . .
 # sorting a column in ascending order
cars.sort_values(by='disp') # by default - Ascending
Out[36]:
Unnamed: 0
mpg
cyl
disp
hp
drat
wt
qsec
vs
am
gear
carb
19
Toyota Corolla
33.9
4
71.1
65
4.22
1.835
19.90
1
1
4
3
18
Honda Civic
30.4
4
75.7
52
4.93
1.615
18.52
1
1
4
6
17
Fiat 128
32.4
4
78.7
66
4.08
2.200
19.47
1
1
4
3
25
Fiat X1-9
27.3
4
79.0
66
4.08
1.935
18.90
1
1
4
3
27
Lotus Europa
30.4
4
95.1
113
3.77
1.513
16.90
1
1
5
6
2
Datsun 710
22.8
4
108.0
93
3.85
2.320
18.61
1
1
4
3
20
Toyota Corona
21.5
4
120.1
97
3.70
2.465
20.01
1
1
3
3
26
Porsche 914-2
26.0
4
120.3
91
4.43
2.140
16.70
0
1
5
6
31
Volvo 142E
21.4
4
121.0
109
4.11
2.780
18.60
1
1
4
6
8
Merc 230
22.8
4
140.8
95
3.92
3.150
22.90
1
1
4
6
29
Ferrari Dino
19.7
6
145.0
175
3.62
2.770
15.50
0
1
5
18
7
Merc 240D
24.4
4
146.7
62
3.69
3.190
20.00
1
1
4
6
0
Mazda RX4
21.0
6
160.0
110
3.90
2.620
16.46
0
1
4
12
1
Mazda RX4 Wag
21.0
6
160.0
110
3.90
2.875
17.02
0
1
4
12
10
Merc 280C
17.8
6
167.6
123
3.92
3.440
18.90
1
1
4
12
9
Merc 280
19.2
6
167.6
123
3.92
3.440
18.30
1
1
4
12
5
Valiant
18.1
6
225.0
105
2.76
3.460
20.22
1
1
3
3
3
Hornet 4 Drive
21.4
6
258.0
110
3.08
3.215
19.44
1
1
3
3
13
Merc 450SLC
15.2
8
275.8
180
3.07
3.780
18.00
0
1
3
9
11
Merc 450SE
16.4
8
275.8
180
3.07
4.070
17.40
0
1
3
9
12
Merc 450SL
17.3
8
275.8
180
3.07
3.730
17.60
0
1
3
9
30
Maserati Bora
15.0
8
301.0
335
3.54
3.570
14.60
0
1
5
24
22
AMC Javelin
15.2
8
304.0
150
3.15
3.435
17.30
0
1
3
6
21
Dodge Challenger
15.5
8
318.0
150
2.76
3.520
16.87
0
1
3
6
23
Camaro Z28
13.3
8
350.0
245
3.73
3.840
15.41
0
1
3
12
28
Ford Pantera L
15.8
8
351.0
264
4.22
3.170
14.50
0
1
5
12
6
Duster 360
14.3
8
360.0
245
3.21
3.570
15.84
0
1
3
12
4
Hornet Sportabout
18.7
8
360.0
175
3.15
3.440
17.02
0
1
3
6
24
Pontiac Firebird
19.2
8
400.0
175
3.08
3.845
17.05
0
1
3
6
16
Chrysler Imperial
14.7
8
440.0
230
3.23
5.345
17.42
0
1
3
12
15
Lincoln Continental
10.4
8
460.0
215
3.00
5.424
17.82
0
1
3
12
14
Cadillac Fleetwood
10.4
8
472.0
205
2.93
5.250
17.98
0
1
3
12
. . .

# sorting a column in descending order
cars.sort_values(by='wt', ascending = False)
Out[37]:
Unnamed: 0
mpg
cyl
disp
hp
drat
wt
qsec
vs
am
gear
carb
15
Lincoln Continental
10.4
8
460.0
215
3.00
5.424
17.82
0
1
3
12
16
Chrysler Imperial
14.7
8
440.0
230
3.23
5.345
17.42
0
1
3
12
14
Cadillac Fleetwood
10.4
8
472.0
205
2.93
5.250
17.98
0
1
3
12
11
Merc 450SE
16.4
8
275.8
180
3.07
4.070
17.40
0
1
3
9
24
Pontiac Firebird
19.2
8
400.0
175
3.08
3.845
17.05
0
1
3
6
23
Camaro Z28
13.3
8
350.0
245
3.73
3.840
15.41
0
1
3
12
13
Merc 450SLC
15.2
8
275.8
180
3.07
3.780
18.00
0
1
3
9
12
Merc 450SL
17.3
8
275.8
180
3.07
3.730
17.60
0
1
3
9
30
Maserati Bora
15.0
8
301.0
335
3.54
3.570
14.60
0
1
5
24
6
Duster 360
14.3
8
360.0
245
3.21
3.570
15.84
0
1
3
12
21
Dodge Challenger
15.5
8
318.0
150
2.76
3.520
16.87
0
1
3
6
5
Valiant
18.1
6
225.0
105
2.76
3.460
20.22
1
1
3
3
10
Merc 280C
17.8
6
167.6
123
3.92
3.440
18.90
1
1
4
12
9
Merc 280
19.2
6
167.6
123
3.92
3.440
18.30
1
1
4
12
4
Hornet Sportabout
18.7
8
360.0
175
3.15
3.440
17.02
0
1
3
6
22
AMC Javelin
15.2
8
304.0
150
3.15
3.435
17.30
0
1
3
6
3
Hornet 4 Drive
21.4
6
258.0
110
3.08
3.215
19.44
1
1
3
3
7
Merc 240D
24.4
4
146.7
62
3.69
3.190
20.00
1
1
4
6
28
Ford Pantera L
15.8
8
351.0
264
4.22
3.170
14.50
0
1
5
12
8
Merc 230
22.8
4
140.8
95
3.92
3.150
22.90
1
1
4
6
1
Mazda RX4 Wag
21.0
6
160.0
110
3.90
2.875
17.02
0
1
4
12
31
Volvo 142E
21.4
4
121.0
109
4.11
2.780
18.60
1
1
4
6
29
Ferrari Dino
19.7
6
145.0
175
3.62
2.770
15.50
0
1
5
18
0
Mazda RX4
21.0
6
160.0
110
3.90
2.620
16.46
0
1
4
12
20
Toyota Corona
21.5
4
120.1
97
3.70
2.465
20.01
1
1
3
3
2
Datsun 710
22.8
4
108.0
93
3.85
2.320
18.61
1
1
4
3
17
Fiat 128
32.4
4
78.7
66
4.08
2.200
19.47
1
1
4
3
26
Porsche 914-2
26.0
4
120.3
91
4.43
2.140
16.70
0
1
5
6
25
Fiat X1-9
27.3
4
79.0
66
4.08
1.935
18.90
1
1
4
3
19
Toyota Corolla
33.9
4
71.1
65
4.22
1.835
19.90
1
1
4
3
18
Honda Civic
30.4
4
75.7
52
4.93
1.615
18.52
1
1
4
6
27
Lotus Europa
30.4
4
95.1
113
3.77
1.513
16.90
1
1
5
6


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