Hi guys i am trying to select a the 2nd value and then add this value to the rest of the array exept the 1st value.
this is what i have so far.
Xloc = X.iloc(1) # selecting the second variable
X = X[1:-1] + Xloc # this doenst work but if i do + 1.25 it works...
the Dataframe
X
0
1.25
2.57
4.5
6.9
7.3
Expected Result
X
0
2.5
3.82
5.75
8.15
8.55
Given that this is your original df
N
0 0.00
1 1.25
2 2.57
3 4.50
4 6.90
5 7.30
you can assign these values and use a simple concat to add in the original value in place
df['M'] = pd.concat([df["N"].iloc[:1], (df["N"].iloc[1:] + df["N"].iloc[1])])
print(df)
N M
0 0.00 0.00
1 1.25 2.50
2 2.57 3.82
3 4.50 5.75
4 6.90 8.15
5 7.30 8.55
Related
I have a dataset in this form:
Name Batch DXYR Emp Lateral GDX MMT CN
Joe 2 0 2 2 2 0
Alan 0 1 1 2 0 0
Josh 1 1 2 1 1 2
Max 0 1 0 0 0 2
These columns can have only three distinct values ie. 0, 1 and 2..
So, I need percent of value counts for each column in pandas dataframe..
I have simply make a loop like:
for i in df.columns:
(df[i].value_counts()/df[i].count())*100
I am getting the output like:
0 90.608831
1 0.391169
2 9.6787899
Name: Batch, dtype: float64
0 95.545455
1 2.235422
2 2.6243553
Name: MX, dtype: float64
and so on...
These outputs are correct but I need it in pandas dataframe like this:
Batch DXYR Emp Lateral GDX MMT CN
Count_0_percent 98.32 52.5 22 54.5 44.2 53.4 76.01
Count_1_percent 0.44 34.5 43 43.5 44.5 46.5 22.44
Count_2_percent 1.3 64.3 44 2.87 12.6 1.88 2.567
Can someone please suggest me how to get it
You can melt the data, then use pd.crosstab:
melt = df.melt('Name')
pd.crosstab(melt['value'], melt['variable'], normalize='columns')
Or a bit faster (yet more verbose) with melt and groupby().value_counts():
(df.melt('Name')
.groupby('variable')['value'].value_counts(normalize=True)
.unstack('variable', fill_value=0)
)
Output:
variable Batch CN DXYR Emp Lateral GDX MMT
value
0 0.50 0.5 0.25 0.25 0.25 0.50
1 0.25 0.0 0.75 0.25 0.25 0.25
2 0.25 0.5 0.00 0.50 0.50 0.25
Update: apply also works:
df.drop(columns=['Name']).apply(pd.Series.value_counts, normalize=True)
Please help me
The below one is the problem...
write an expression to extract a new dataframe containing those days where the temperature reached at least 70 degrees, and assign that to the variable at_least_70. (You might need to think some about what the different columns in the full dataframe represent to decide how to extract the subset of interest.)
After that, write another expression that computes how many days reached at least 70 degrees, and assign that to the variable num_at_least_70.
This is the original DataFrame
Date Maximum Temperature Minimum Temperature \
0 2018-01-01 5 0
1 2018-01-02 13 1
2 2018-01-03 19 -2
3 2018-01-04 22 1
4 2018-01-05 18 -2
.. ... ... ...
360 2018-12-27 33 23
361 2018-12-28 40 21
362 2018-12-29 50 37
363 2018-12-30 37 24
364 2018-12-31 35 25
Average Temperature Precipitation Snowfall Snow Depth
0 2.5 0.04 1.0 3.0
1 7.0 0.03 0.6 4.0
2 8.5 0.00 0.0 4.0
3 11.5 0.00 0.0 3.0
4 8.0 0.09 1.2 4.0
.. ... ... ... ...
360 28.0 0.00 0.0 1.0
361 30.5 0.07 0.0 0.0
362 43.5 0.04 0.0 0.0
363 30.5 0.02 0.7 1.0
364 30.0 0.00 0.0 0.0
[365 rows x 7 columns]
I wrote the code for the above problem is`
at_least_70 = dfc.loc[dfc['Minimum Temperature']>=70,['Date']]
print(at_least_70)
num_at_least_70 = at_least_70.count()
print(num_at_least_70)
The Results it is showing
Date
204 2018-07-24
240 2018-08-29
245 2018-09-03
Date 3
dtype: int64
But when run the test case it is showing...
Incorrect!
You are not correctly extracting the subset.
As suggested by #HenryYik, remove the column selector:
at_least_70 = dfc.loc[dfc['Maximum Temperature'] >= 70,
['Date', 'Maximum Temperature']]
num_at_least_70 = len(at_least_70)
Use boolean indexing and for count Trues of mask use sum:
mask = dfc['Minimum Temperature'] >= 70
at_least_70 = dfs[mask]
num_at_least_70 = mask.sum()
I have this dataframe:
value limit_1 limit_2 limit_3 limit_4
10 2 3 7 10
11 5 6 11 13
2 0.3 0.9 2.01 2.99
I want to add another column called class that classifies the value column this way:
if value <= limit1.value then 1
if value > limit1.value and <= limit2.value then 2
if value > limit2.value and <= limit3.value then 3
if value > limit3.value then 4
to get this result:
value limit_1 limit_2 limit_3 limit_4 CLASS
10 2 3 7 10 4
11 5 6 11 13 3
2 0.3 0.9 2.01 2.99 3
I know I could work to get these 'if's to work but my dataframe has 2kk rows and I need the fasted way to perform such classification.
I tried to use .cut function but the result was not what I expected/wanted
Thanks
We can use the rank method over the column axis (axis=1):
df["CLASS"] = df.rank(axis=1, method="first").iloc[:, 0].astype(int)
value limit_1 limit_2 limit_3 limi_4 CLASS
0 10 2.0 3.0 7.00 10.00 4
1 11 5.0 6.0 11.00 13.00 3
2 2 0.3 0.9 2.01 2.99 3
We can use np.select:
import numpy as np
conditions = [df["value"]<df["limit_1"],
df["value"].between(df["limit_1"], df["limit_2"]),
df["value"].between(df["limit_2"], df["limit_3"]),
df["value"]>df["limit_3"]]
df["CLASS"] = np.select(conditions, [1,2,3,4])
>>> df
value limit_1 limit_2 limit_3 limit_4 CLASS
0 10 2.0 3.0 7.00 10.00 4
1 11 5.0 6.0 11.00 13.00 3
2 2 0.3 0.9 2.01 2.99 3
I have two dataframes for groundtruth and predicted trajectories and one dataframe for matching between the groundtruth and predicted trajectories at each frame. I have dataframe of the groundtruth tracks and predicted tracks as follows:
df_pred_batch =
CENTER_X CENTER_Y LENGTH SPEED ACCELERATION HEADING
FrameId HId
0 0 -1.870000 -0.41 1.51 1.280 1.670 0.39
1 0 -1.730000 -0.36 1.51 1.440 1.660 0.40
2 0 -1.180000 -1.57 2.05 2.220 0.390 0.61
0 1 -1.540000 -1.83 2.05 2.140 0.390 0.61
1 1 -1.370000 -1.70 2.05 2.180 0.390 0.61
2 1 -1.590000 -0.29 1.51 1.610 1.630 0.41
1 2 -1.910000 -1.12 1.04 0.870 1.440 0.30
2 2 -1.810000 -1.09 1.04 1.010 1.440 0.27
0 3 17.190001 -3.15 1.80 2.178 -0.028 3.36
1 3 15.000000 -3.60 1.80 2.170 -0.020 3.38
df_gt_batch =
CENTER_X CENTER_Y LENGTH SPEED ACCELERATION HEADING
FrameId OId
1 0 -1.91 -1.12 1.040 0.87 1.44 0.30
2 0 -1.81 -1.09 1.040 1.01 1.44 0.27
0 1 -1.87 -0.41 1.510 1.28 1.67 0.39
1 1 -1.73 -0.36 1.510 1.44 1.66 0.40
2 1 -1.59 -0.29 1.510 1.61 1.63 0.41
0 2 -1.54 -1.83 2.056 2.14 0.39 0.61
1 2 -1.37 -1.70 2.050 2.18 0.39 0.61
2 2 -1.18 -1.57 2.050 2.22 0.39 0.61
0 3 1.71 -0.31 1.800 2.17 -0.02 3.36
1 3 1.50 -0.36 1.800 2.17 -0.02 3.38
2 3 1.29 -0.41 1.800 2.17 -0.01 3.40
Also, I know their matching at each timestamp:
matched_gt_pred =
FrameId Type OId HId
0 0 MATCH 1.0 0.0
1 0 MATCH 2.0 1.0
4 1 MATCH 1.0 0.0
5 1 MATCH 2.0 1.0
6 1 MATCH 0.0 2.0
9 2 MATCH 0.0 2.0
I would like to look at each row of matched_gt_pred and get the corresponding CENTER_X from df_pred_batch and df_gt_batch and calculate the error.
For instance looking at the first row of the matched_gt_pred I know at FrameId == 0 and OId == 1 and HId == 0 are matched. I should get the Center_X from gt_center_x = df_gt_batch["FrameId==0" and "OId == 1"].CENTER_X and pred_center_x = df_pred_batch["FrameId==0" and "HId == 0"].CENTER_X And compute error = abs(gt_center_x - pred_center_x)
IIUC, I would reshape your df_gt_batch and df_pred_batch and use lookup:
gt_x = df_gt_batch['Center_X'].unstack().lookup(match_gt_pred['FrameId'], match_gt_pred['OId'])
pred_x = df_pred_batch['Center_X'].unstack().lookup(match_gt_pred['FrameId'], match_gt_pred['HId'])
match_gt_pred['X Error'] = np.abs(gt_x - pred_x)
Output:
FrameId Type OId HId X Error
0 0 MATCH 1.0 0.0 0.0
1 0 MATCH 2.0 1.0 0.0
4 1 MATCH 1.0 0.0 0.0
5 1 MATCH 2.0 1.0 0.0
6 1 MATCH 0.0 2.0 0.0
9 2 MATCH 0.0 2.0 0.0
Another option is to use reindex with pd.MultiIndex:
match_gt_pred['X Error'] = (df_pred_batch.reindex(pd.MultiIndex.from_arrays([match_gt_pred['FrameId'], match_gt_pred['HId']]))['Center_X'].to_numpy() -
df_gt_batch.reindex(pd.MultiIndex.from_arrays([match_gt_pred['FrameId'], match_gt_pred['OId']]))['Center_X'].to_numpy())
I have a problem which I cannot seem to get my head round.
df1 is as follows:
Group item Quarter price quantity
1 A 2017Q3 0.10 1000
1 A 2017Q4 0.11 1000
1 A 2018Q1 0.11 1000
1 A 2018Q2 0.12 1000
1 A 2018Q3 0.11 1000
Result desired is a new dataframe call it df2 with an additional column.
Group item Quarter price quantity savings/lost
1 A 2017Q3 0.10 1000 0.00
1 A 2017Q4 0.11 1000 0.00
1 A 2018Q1 0.11 1000 0.00
1 A 2018Q2 0.12 1000 0.00
1 A 2018Q3 0.11 1000 10.00
1 A 2018Q4 0.13 1000 -20.00
Essentially, I want to go down each row, look at the quarter and find last year's similar quarter and do a calculation (price this quarter - price last quarter * quantity). If there are no previous quarter data, just have in the last column.
And to complete the picture, there are more groups and items in there, and even more quarters like 2016Q1, 2017Q1, 2018Q1 although i only need compare the year before. Quarters are in string format.
Use pandas.DataFrame.shift
The code below assumes that your column Quarter is sorted and there is no missing quarters. You can try with the below code:
# Input dataframe
Group item Quarter price quantity
0 1 A 2017Q3 0.10 1000
1 1 A 2017Q4 0.11 1000
2 1 A 2018Q1 0.11 1000
3 1 A 2018Q2 0.12 1000
4 1 A 2018Q3 0.11 1000
5 1 A 2018Q4 0.13 1000
# Code to generate your new column 'savings/lost'
df['savings/lost'] = df['price'] * df['quantity'] - df['price'].shift(4) * df['quantity'].shift(4)
# Output dataframe
Group item Quarter price quantity savings/lost
0 1 A 2017Q3 0.10 1000 NaN
1 1 A 2017Q4 0.11 1000 NaN
2 1 A 2018Q1 0.11 1000 NaN
3 1 A 2018Q2 0.12 1000 NaN
4 1 A 2018Q3 0.11 1000 10.0
5 1 A 2018Q4 0.13 1000 20.0
Update
I have updated my code to handle two things, first sort the Quarter and second handle the missing Quarter scenario. For grouping based on columns you can refer pandas.DataFrame.groupby and many pd.groupby related questions already answered in this site.
#Input dataframe
Group item Quarter price quantity
0 1 A 2014Q3 0.10 100
1 1 A 2017Q2 0.16 800
2 1 A 2017Q3 0.17 700
3 1 A 2015Q4 0.13 400
4 1 A 2016Q1 0.14 500
5 1 A 2014Q4 0.11 200
6 1 A 2015Q2 0.12 300
7 1 A 2016Q4 0.15 600
8 1 A 2018Q1 0.18 600
9 1 A 2018Q2 0.19 500
#Code to do the operations
df.index = pd.PeriodIndex(df.Quarter, freq='Q')
df.sort_index(inplace=True)
df2 = df.reset_index(drop=True)
df2['Profit'] = (df.price * df.quantity) - (df.reindex(df.index - 4).price * df.reindex(df.index - 4).quantity).values
df2['Profit'] = np.where(np.in1d(df.index - 4, df.index.values),
df2.Profit, ((df.price * df.quantity) - (df.price.shift(1) * df.quantity.shift(1))))
df2.Profit.fillna(0, inplace=True)
#Output dataframe
Group item Quarter price quantity Profit
0 1 A 2014Q3 0.10 100 0.0
1 1 A 2014Q4 0.11 200 12.0
2 1 A 2015Q2 0.12 300 14.0
3 1 A 2015Q4 0.13 400 0.0
4 1 A 2016Q1 0.14 500 18.0
5 1 A 2016Q4 0.15 600 0.0
6 1 A 2017Q2 0.16 800 38.0
7 1 A 2017Q3 0.17 700 -9.0
8 1 A 2018Q1 0.18 600 -11.0
9 1 A 2018Q2 0.19 500 0.0